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MANUAL OF PHYSICAL GEOGRAPHY 



THE MACMILLAN COMPANY 

NEW YORK • BOSTON • CHICAGO 
ATLANTA • SAN FRANCISCO 

MACMILLAN & CO., Limited 

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THE MACMILLAN CO. OF CANADA, Ltd. 

TORONTO 



MANUAL 



OF 



PHYSICAL GEOGRAPHY 



BY 



FREDERICK VALENTINE EMERSON, Ph.D. 

INSTRUCTOR IN GEOLOGY IN THE UNIVERSITY 
OF MISSOURI 



Nefo 3f0tfc 

THE MACMILLAN COMPANY 

1909 

All rights reserved 



5 b 



^V 



Copyright, 1909, 
By THE MAOMILLAN COMPANY. 

Set up and electrotyped. Published December, 1909. 



NoriDootr ^ress 

J. S. Gushing Co. — Berwick & Smith Co. 

Norwood, Mass., U.S.A. 



'CU252963 



PREFACE 

The exercises in this " Manual " have, for the most 
part, grown out of the author's class-room experiences. 
There is presented a variety of exercises, some of them 
advanced in character, that will cover the topics capable 
of laboratory illustration usually presented in a course 
in physical geography. For such classes as cannot use 
the entire " Manual," the author suggests a selected list 
of exercises which are starred (*). Most of the exer- 
cises can be used in a different order from that given 
by omitting the references to other exercises. 

Some of the exercises and their order of presentation 
may require explanation. Considerable attention is 
given to elementary principles of mathematical geog- 
raphy. Many students of this phase of the science 
seem to have a vocabulary rather than an understand- 
ing of it. For example, rather few students know pre- 
cisely why it is colder in winter than in summer, 
or why the seasons change. The author would urge 
thorough drill in these elementary principles and in the 
elementary facts of insolation. Climate is treated early 



vi PREFACE 

in the course in order that a foundation may be laid 
for intelligent weather observations throughout the year. 
Especial attention is given to the cyclone, since it is 
the main climatic factor in the United States. If the 
teacher prefers to postpone the consideration of climate 
until later in the course, it can be done without incon- 
venience. 

In presenting land forms due to normal erosion, the 
author has been most successful in grouping them 
according to their structure. Looked at in this way, 
the different types of mountains, for example, are pro- 
duced by erosion acting upon different structures. Con- 
structive imagination is brought out and a valuable 
discipline is secured.- The author is aware that this 
plan leads into structural geology farther than many 
teachers care to go. The questions are therefore arranged 
so that the facts of structure can be omitted and the 
topographic facts studied by themselves. The topics 
of soils and harbors are introduced because they are 
geographic factors so important that every student 
should know of them. 

It is the author's conviction that physical geography 
should lead up to, and should include a study of, the 
United States. To this end a series of exercises has 
been provided in Chapter XVIII to present important 
typical regions. Further reasons for these exercises 



PREFACE vii 

are that the preceding principles may be reviewed and 
that the student may gain facility in studying large 
areas. Few sciences offer better opportunities than 
physical geography for studying large units and group- 
ing their various phenomena. 

Wherever possible for the sake of economy, the same 
quadrangles have been used in different exercises. For 
those who wish to show the same features on different 
quadrangles, the United States Geological Survey has 
issued a useful pamphlet, " Topographic Maps of the 
United States showing Physiographic Types," which will 
be sent on application. 

Most of the climatic tables have been taken from 
Hann's ' Cl Lehrbuch der Meteorologie," second edition, 
from " Climatology of the United States " by Alfred J. 
Henry, and from various tables published by the Smith- 
sonian Institution. Many suggestions have been derived 
from " Climate " by Professor R. DeC. Ward and from 
the same author's " Handbook of Meteorology," from 
which the method in Exercise 27 is taken. 

The thanks of the author are due to various Weather 
Bureau officials who have kindly furnished data ; to 
Dr. J. A. Bonsteel, of the United States Soil Survey, 
who read the manuscript of the chapter on Soils ; to 
Professor C. F. Marbut, of the University of Missouri, 
who has aided in many ways. The author is especially 



Vlll PREFACE 

indebted to Professor George D. Hubbard, of the Ohio 
State University, who read the manuscript and made 
many valuable suggestions. 

FREDERICK V. EMERSON. 
Columbia, Missouri, 

June, 1909. 



CONTENTS 

CHAPTER I 
The Earth as a Planet 

PAGE 

1. The Form of the Earth 1 

*Part I ; Part II 1 

*2. The Earth's Axis 3 

Parts I, II, and III . . . . 3 

3. Length of Day and Night 5 

4. Longitude and Time . . . 7 

5. To ascertain the Noon Hour 8 

6. Longitude 8 

7. To ascertain the Local Latitude 9 

8. Revolution of the Earth 10 

•Parti; Part II 10 

CHAPTER II 

Climate — Temperature 

*9. Diurnal Insolation 12 

*10. Insolation at Various Latitudes 13 

11. Insolation, Length of Day, and Temperature in Norway . 15 

*12. Maxima of Temperature due to Insolation .... 16 

*13. Continental and Marine Average Annual Temperatures . . 16 

*14. Hourly Temperatures 17 

1.5. Temperatures on the East and West Shores of the Atlantic . 18 

*16. Temperature and Altitude .19 

CHAPTER III 

Moisture of the Atmosphere 

*17. Capacity and Temperature .20 

*18. Observations of Relative Humidity 20 



X CONTENTS 

PAGE 

*19. Diurnal Relative Humidity 23 

20. Absolute Humidity and Relative Humidity in Continental 

and in Marine Climates 24 

21. Climate during August, 1896 25 

*22. Equatorial Rainfall 26 

*23. Tropical Rainfall 26 

24. Monsoonal Type of Rainfall 27 

CHAPTER IV 

Cyclones and Anticyclones 



*25. General Map Study of a Cyclone 

*26. Construction of a Weather Map 

*27. Wind Directions in Cyclones and Anticyclones 

*28. Isotherms in Cyclones and Anticyclones . 

*29. State of Sky in Cyclones and Anticyclones 

30. Inference of a Cyclone or an Anticyclone from Wind Direction 

31. Inference of Cyclones and Anticyclones from Isotherms . 

32. Conditions in Different Parts of Cyclones and Anticyclones 

33. Cyclones and Anticyclones in Summer and in Winter 
*34. Cyclone Paths 



28 
29 
34 
35 
35 
36 
37 
38 
41 
42 



CHAPTER V 

Miscellaneous Climatic Phenomena 

*35. A Land and Sea Breeze 43 

36. A Chinook Wind 44 

*37. Observation of a Rain Storm 45 

38. The Dew-point .46 

*39. Observations on Dew Deposition ...... 46 

40. Study of a Fog .47 

•41. Cloud Study 47 

*42. Observations of Frost Conditions 48 

43. Map Study of Frost Conditions 49 

*44. Local Forecasting . .50 

45. Trade Winds and Sailing Routes 51 

*46. Local Study 53 



CONTENTS xi 

CHAPTER VI 
Common Minerals and Rocks 

PAGE 

*47. Common Minerals 54 

*48. Common Rocks 55 

*49. Field Study of a Rock Outcrop 59 

CHAPTER VII 

The Contour Map 

*50. Construction of a Contour Map 60 

CHAPTER VIII 

Weathering, Streams and Stream Valleys 

*51. Field Study of Weathering 66 

*52. Field Study of Stream Work . . 67 

53. Weathering and Corrasion Curves 72 

*54. Map Study of Streams and Stream Valleys .... 74 

55. Reversed Stream Tributaries 76 

*56. Braided (Anastomosing) Streams 77 

*57. Flood Plains 78 

*58. A Graded River 79 

59. Mississippi Delta 80 

60. Alluvial Fans 82 

•Part I ; Part II 82 

61. River Deposits. Bars 85 

62. Flood Plain Meanders .85 

*PartI; Part II 85 

63. River Terraces 87 

•Part I; Part II 87 

64. Stream Capture 88 

*Part I ; Part II 88 

65. Youthful Topography and Drainage 91 

*Parts I, *II, III, IV, *V 91 

66. Mature Rivers and Valleys 95 



xii CONTENTS 

PAGE 

♦Part I ; Part II ...... . . . 95 

*67. Early Mature Topography . . ' . . . . .97 

*68. Mature Topography and Drainage 98 

69. A Region in Old Age 99 

70. A Stream in Old Age 99 

71. A Region in Old Age, recently Revived 100 

*72. Review. The Cycle of Erosion 100 

*73. A Peneplain recently Elevated 101 

74. A Rejuvenated or Revived River 101 

75. Incised (Intrenched) Meanders 103 

76. A Superimposed Stream . . . . . . . . 104 

*77. Drowned Stream Valleys . . . . . . .105 

78. Field Study of Consequent, Insequent, and Subsequent Streams 106 

79. Map Study of Consequent, Insequent, and Subsequent Streams 

and their Associated Valley Patterns . . . . . 107 

*80. Study of a Canon 109 

*81. Study of a Waterfall 110 

CHAPTER IX 

Land Forms in Various Rock Structures. Stratified 
and Homogeneous Rocks 



*82. Hills and Valleys in Stratified Rocks of Varying Strength 

83. Mountains of Circumerosion (Circumdenudation) 

84. Mountains in Youth (Circumerosion) 

85. Mountains of Circumerosion in Maturity . 
*86. Escarpments 

87. Escarpment and Outliers .... 

88. A Maturely Dissected Mountainous Divide 
Part I ; Part II 



113 
114 
115 

116 
116 
117 
118 
118 



CHAPTER X 

Land Forms in Folded and Tilted Rocks 

*89. Young Anticlinal Mountain and Synclinal Valleys . . 121 
90. An Anticlinal Mountain (Unsymmetrically Folded) . . 122 



CONTENTS 



Xlll 



PAGE 

91. An Anticlinal Valley 123 

*92. An Eroded Anticline with Monoclinal Ridges . . . 124 

93. Synclinal Mountains 126 

*94. Eroded Synclines ; Monoclinal Ridges 127 

95. A Syncline with Pitching Axis 128 

96. Land Forms resulting from the Erosion of a Pitching Anti- 

cline 130 

97. Stream Adjustment in Folded Structure .... 132 
*98. Stream Capture in Folded Rocks 134 

99. The Effect of a Change in Dip upon the Width of Outcrop . 135 

Part I ; Part II 135 

100. Peneplains 136 

*101. Stage of Erosion in Topography developed on Folded Rocks 138 
102. Monoclinal Shifting .... . . . .138 

•103. "Hog Backs" 139 

104. A Cuesta 141 

CHAPTER XI 
Land Forms due to Faulting and Volcanism 



105. Fault Scarps 

*PartI; Part II .... 

*106. Block Mountain and Rift Valley . 

107. Review of Forms due to Folding and to 

*108. A Volcanic Mountain 

*109. A Dissected Volcanic Mountain 

110. Laccolithic Mountains 

*111. A Volcanic Neck .... 

112. Topography due to a Dike 

*113. Lava Cones and Cinder Cones. 

*114. A Sill 



Faulting 



143 
143 
144 
146 
147 
148 
149 
149 
150 
150 
151 



CHAPTER XII 

Glaciation 



*115. Alpine or Mountain Glaciers 
116. Cirques .... 



152 
152 



XIV CONTENTS 

PAGE 

*117. U-shaped and Hanging Lateral Valleys 154 

*118. Marginal Moraines . . . ■ ■ 155 

*119. Comparison of Ground Moraine and Marginal Moraine . 157 
120. Comparison of Mountains modified by Mountain Glaciation 

and by Continental Glaciation 157 

*121. A Comparison of Mountains affected by Glacial Erosion and 

by Subaerial Erosion 158 

*122. Fiords 158 

*123. A Glacially Diverted Stream 160 

*124. Drumlins 161 

125. Comparison of Glacial Erosion and Glacial Deposition . .162 

126. Sand Plains and Ice-contact Slopes 162 

127. General Exercise .163 

128. General Review 165 

*129. A Comparison of Driftless, New Drift, and Older Drift Areas 166 

CHAPTER XIII 

Lakes 

*130. An Ox-bow Lake 170 

*131. Lakes and Swamps on a Flood Plain 170 

132. Delta Lakes . .170 

133. Lakes in Rock Basins 171 

•134. An Ice-blocked Valley 171 

*135. Morainic Lakes 171 

136. An Extinct Glacial Lake 172 

137. A Crater Lake 173 

138. Consequent and Solution Lakes 175 

139. Lakes due to Faulting 175 

140. A Nearly Drained Lake . 176 

*141. Lakes as Filters 176 

CHAPTER XIV 

The Ocean 

*142. The Floor of the Atlantic . 177 

*143. The Continental Shelf 178 



CONTENTS 



XV 



PAGE 

*144. Daily Tides 178 

*145. Daily High Tides . .179 

146. Tides on a Smooth and an Indented Coast .... 180 

147. Lagging of the Tides 181 

148. Tidal Currents 182 

*149. Oceanic and Coastal Tides . . . . . . .182 

*150. Ocean Currents 183 

151. An Atoll 184 

*152. Coral Reefs 185 



CHAPTER XV 

Shore Lines and Forms 

*153. Comparison of Subaerial and Submarine Topography . . 187 

154. A Young Coast 188 

*155. Off-shore Bars 189 

156. Sea Cliffs and Wing Spits 191 

157. Tied Islands 194 

158. Shore Lines of Extinct Lakes 195 

*159. A Risen Coast 197 

160. A Young Risen Coast with a Narrow Coastal Plain . . 198 

161. Elevated Wave-cut Terraces and Cliffs 198 

162. A Tidal Delta 199 

163. General Exercise 200 



CHAPTER XVI 



Harbors 



*164. Introduction 

*165. A Drowned Valley Harbor 

*166. A River Harbor 

*167. A Moraine Harbor . 

*168. A Bar Harbor 

*169. San Francisco Harbor 

170. A Coral Reef Harbor 
♦Part I ; Part II 



203 
204 
205 
206 
206 
208 
209 
209 



XVI 



CONTENTS 



PAGE 

*171. A Fiord Harbor ... 210 

172. An Atoll Harbor . . . . . . . . .211 

173. A Hook Harbor . . . ' .211 

174. A Spit Harbor 211 

175. A Tied Island Harbor . . 212 

CHAPTER XVII 



Soils 

*176. Soils along an Aggrading River 

*177. Soils on Alluvial Fans .... 

178. Valley Soils due to Wash from the Uplands 

*179. Soils on River Terraces .... 

*180. Soils on Lake Shores and Bottoms . 

181. Soils in a Region of Ridges 

182. Soils in Central Florida .... 

183. Soils on Ground Moraine and Drumlins . 
*184. Soils on a Moraine and Outwash Plain . 



213 
214 

215 
216 
216 
217 
218 
218 
219 



CHAPTER XVIII 



Studies op Typical Areas 

*185. A Youthful Plain ; The Red River Valley . . . .220 

*186. Mature and Old Plains, Kansas 223 

*187. The Ontario Plain and the Alleghany Plateau, New York . 224 
*188. The Coastal Plain, Piedmont Plateau, and Highlands in New 

Jersey . 228 

189. The Coastal Plain, Piedmont Plateau, Blue Ridge, Great 

Valley, Ridge Belt, and Alleghany Plateau in Maryland, 

Virginia, and West Virginia 232 

*190. The Piedmont Plateau, Blue Ridge, Appalachian Valley, 

Cumbei'land Plateau, and Nashville Basin .... 237 

191. A Portion of the Ridge Belt and the Great Valley in Penn- 

sylvania ' . . 244 

*Part I ; Part II . 244 

192. The Coastal Plain in Florida 246 

*193. The Lower Mississippi Valley . . ; . . .248 



CONTENTS 



XV11 



*194. Southern New England. Connecticut 

195. The Black Hills and the Great Plains . 

*196. The Eastern Margin of the Rocky Mountains and the Adja- 
cent Great Plains ..... 

*197. The Eastern Border of the Great Basin . 

*198. The Plateau of Arizona and the Grand Canon 

*199. The Western Great Basin and the Sierras 

*200. The Sierras in California 

201. The Northern Cascade Mountains and the Columbia Plateau 

Appendix . . . 

Index 



PAGE 

249 
252 

255 
256 
261 
264 
266 
271 

275 

285 



" Effective power in action is the true end of education." 

— Eliot. 



MANUAL OF PHYSICAL GEOGRAPHY 

CHAPTER I 

THE EARTH AS A PLANET 
1. FORM OF THE EARTH 

* Part I. — One of the best ways by which the form of 
the earth has been determined is the measurement of 
degrees of latitude on different parts of the earth's sur- 
face. If the earth were a perfect sphere, would the 
degrees of latitude be equal 
in all parts of the earth ? 
If the earth were a spheroid 
as in Figure 1, what part of 
the spheroid would be a por- 
tion of a large circle ? Why ? 
Of a small circle ? Why ? 
In what part of Figure 1 

would the latitude degrees be longest ? Why ? Short- 
est ? Why ? 

Part II. — Make a graph illustrating the length of 
latitude degrees as given in the table. A graph is a 
line drawn to illustrate a table of facts. Upon your 




MANUAL OF PHYSICAL GEOGRAPHY 



coordinate paper allow the heavy vertical lines to rep- 
resent every ten degrees of latitude. Allow each lighter 
horizontal line to represent j^-q of a mile. Take the 
lowest corner to represent the lowest value in your table 
as a starting point. In this table this lowest value rep- 
resents the length of the latitude degree at the equa- 
tor. The length for 5° latitude is 68.71, and the point 
representing this value is at the intersection of the 5° 
line and the line representing 68.71 miles. Finish the 
location of points for each value, connect the points, 
and you have the graph. 



Length of Degrees of Latitude at Various Latitudes 



Latitude 


Miles 


Latitude 


Miles 


Latitude 


Miles 





68.704 


35 


68.935 


65 


69.281 


5 


68.710 


40 


68.993 


70 


69.324 


10 


68.725 


45 


69.054 


75 


69.360 


15 


68.751 


50 


69.115 


80 


69.386 


20 


68.786 


55 


69.175 


85 


69.402 


25 


68.829 


60 


69.230 


90 


69.407 


30 


68.879 











Is the graph a straight line ? Does the graph indi- 
cate constant or changing values ? Plot on same sheet 
a graph, assuming that the degrees are 68.70 miles long 
the world over. Is this a straight line ? Why ? Plot 
on the same sheet a graph, assuming that the latitude 
degrees increase j±^ of a mile for each 5° of latitude. 



THE EARTH AS A PLANET 



Is it a straight line ? Why ? Compare your three 
graphs as to straightness and direction. Does your 
graph of latitude degrees show increasing or decreas- 
ing values ? Where is the greatest increase ? Where 
the least ? What does this show about the curvature 
of the earth ? Where is the curvature greatest, at the 
equator or at 50° ? At 20° or at 60° ? 

•2. THE EFFECTS OF THE INCLINATION OF THE 
EARTH'S AXIS 

Part I. — To find the effect of the inclination of the 
earth's axis to the plane of the orbit, an apparatus 




Fig. 2. 



shown in Figure 2 x will be useful. The horizontal 
wire represents the rays of the sun. First keeping the 

1 See Appendix. 



4 MANUAL OF PHYSICAL GEOGBAPHY 

axis vertical and parallel to its first position, move the 
earth in a circle, also moving the wire. Does the wire 
always point to the same latitude on the globe ? How 
much of the earth is illuminated ? Pass a cord or rubber 
band around the globe, dividing the illuminated and 
non-illuminated portions. Placing the globe so that the 
wire points to the equator, move the earth in a circle. 
Are the hemispheres equally illuminated ? Change the 
inclination of the axis to about 23J°. Move the globe 
in a circle as before. Do the rays point always to the 
same latitude ? If not, through how great a range of 
latitude are the rays vertical ? Are the hemispheres 
equally illuminated at all times ? At any times ? 
Change the inclination of the axis to 10° ; 50° ; 90°. 
Compare in all respects with your previous results. 

Part II. — Move the globe in a circle, but do not keep 
the axis parallel to its first position. How do your 
results compare with those in Part I ? 

Part III. — Referring to Parts I and II, what area of 
the globe receives direct rays of the sun at some time 
of the year ? How wide is this area ? How much beyond 
the poles does the circle of illumination extend ? (The 
circle of illumination divides the lighted from the dark 
parts of the earth.) What is the tropical zone ? What 
is its width ? What determines its limits ? What is the 
width of the polar zones ? What determines their limits? 



THE EARTH AS A PLANET 5 

3. LENGTH OF DAY AND NIGHT 

The reason for the varying length of day and night 
is often not thoroughly understood. Do not leave the 
topic until you can demonstrate it. 

Take a globe and apparatus as in Exercise 2. How 
much of the earth is illuminated ? Can it ever be more ? 
Less? The boundary of the illuminated part is called 
the circle of illumination. Is it a great circle (i.e. does 
it always bisect the earth) ? Place the globe in its posi- 
tion at equinox. Does the circle of illumination bisect 
the equator ? The other parallels ? What, therefore, is 
the length of day and night over the globe ? Place the 
globe in the position of the June solstice. Is the equa- 
tor bisected by the circle of illumination ? Is the Tropic 
of Cancer ? The Tropic of Capricorn ? Are days and 
nights equal at the equator ? Why ? At the Tropic of 
Capricorn ? Why ? At the Tropic of Cancer ? Why ? 
Are days and nights always equal at the equator ? 
Why ? When only are they equal at other places ? 

Taking a given point, say your home city or some 
other city, follow it through the illuminated and non- 
illuminated portions of the earth at the June solstice. 
Does it pass for the greater distance through the illumi- 
nated or non-illuminated portions ? Follow the same 
study for the December solstice. 

It will now be apparent that unequal length of day 



6 MANUAL OF PHYSICAL GEOGRAPHY 

and night is due to the unequal division of the northern 
and southern hemispheres by the circle of illumination. 
That is, when the days are long, these hemispheres pass 
through a smaller shadow than when the days are short. 
The principle can be well shown by the ajDparatus shown 
in Figure 3. Take a globe (a slated globe is preferable) 

Jt ^ and compass. With one .leg 

of the compass on the equator 
and the compass opening equal 
to the radius of the globe, 
the circle described will pass 
through the poles. This circle 
will represent the circle of illu- 
mination with the sun at its 
center. What time of the year 
is represented ? Moving the 
FlG - 3 - leg of the compass north or 

south of the equator in the same way as the sun's 
vertical rays move, the circle of illumination can be 
shown for various positions of the sun. With this in 
mind demonstrate the following problems : — 

When the vertical rays are 5° north of the equator, 
what is the location of the circle of illumination near 
the North Pole ? Near the South Pole ? What is the 
position of the circle of illumination when the vertical 
rays are 20° north of the equator ? When they are 23 J° 
south of the equator ? 




THE EARTH AS A PLANET 7 

From the following table plot graphs showing the 
length of day for 60° north and 60° south. (Use the 
length of day in minutes for plotting.) Why are the 
graphs pointed in opposite directions ? Plot on another 
sheet of paper the graphs for 30° north and 30° south. 
(Use the same scale for each.) In which set of graphs 
is the greatest length of day shown ? Why ? The 
least ? Why ? Which graphs show the greatest range 
of length of day ? Why ? 

Table showing the Duration op Direct Sunlight on the Fif- 
teenth of each Month for Latitude : 60° North, 60° South, 
30° North, and 30° South 





60° North 


60° South 


30° North 


30° South 




hr. m. 


m. 


hr. m. 


m. 


hr. 


m. m. 


hr. m. m. 


January- 


6 19 


379 


17 41 


1061 


10 


16 616 


13 44 824 


February 


8 51 


531 


15 9 


909 


10 


58 658 


13 2 782 


March 


11 30 


690 


12 30 


750 


11 


50 710 


12 10 730 


April 


14 18 


858 


9 42 


582 


12 


45 765 


11 15 675 


May 


16 50 


1010 


7 10 


430 


13 


31 811 


10 29 629 


June 


18 26 


1106 


5 34 


334 


13 


55 835 


10 5 605 


July 


17 46 


1066 


6 14 


374 


13 


46 826 


10 14 614 


August 


15 27 


927 


8 33 


513 


13 


7 787 


10 53 653 


September 


12 43 


763 


11 17 


677 


12 


14 734 


11 46 706 


October 


10 


600 


14 


840 


11 


21 681 


12 39 759 


November 


7 17 


437 


16 43 


1003 


10 


31 631 


13 29 809 


December 


5 35 


335 


18 25 


1105 


10 


5 605 


13 55 835 



4. LONGITUDE AND TIME 

How long does it take the earth to make one rota- 
tion f Through how many degrees does the earth turn 



8 MANUAL OF PHYSICAL GEOGRAPHY 

to make one rotation ? Through how many degrees 
does it rotate in an hour ? In a minute ? In a second ? 
What is the difference in time between two places 45° 
of longitude apart ? What is the difference in time be- 
tween two places 65° apart ? 90° apart ? 

If two places have a difference in time of 2 hours, 
how many degrees of longitude are they apart ? How 
many if they have a difference in time of 3 hours 30 
minutes ? Of 6 hours 45 minutes ? What is the dif- 
ference in solar time between New York (74°) and San 
Francisco (122° 29') ? New York and Chicago (87° 36') ? 
Between New York and your own or nearest city ? 

5. TO ASCERTAIN THE NOON HOUR 

From a south window hang a plumb line. Measure 
its shadow at different hours of the day and record 
their lengths. Plot these lengths. How do the shad- 
ows behave as noon is approached ? As noon is 
receded from ? Why is this so ? What shadow, the 
longest or the shortest, represents noon ? Why ? (A 
perpendicular post will answer the same purpose as the 

plumb line.) 

6. LONGITUDE 

Arredono, Fla., and Nome, Alaska, Quadrangles. 
What are the latitudes of the Florida and Alaska maps ? 
What difference in latitudes ? What is the scale of the 
maps? What is the length (in miles) of five minutes of 



THE EARTH AS A PLANET 9 

longitude on the Florida map ? What therefore is the 
length of a degree here ? What is the length of a de- 
gree on the Alaska map ? What is the reason for this 
change in length ? What is the length of a degree of 
longitude at the poles ? You will note that the Alaska 
map is narrower at the top than at the bottom. Why 
is this ? Do the Florida maps show as much narrow- 
ing ? Why ? Draw to illustrate. 

7. TO ASCERTAIN THE LOCAL LATITUDE 

Using the same apparatus as in Exercise 5, find the 
length of the shadow. This should preferably be done 
at one of the equinoxes. Measure ^ A 

the shadow BC (Figure 4) at noon. 
The angle ABC represents the altitude 
of the sun. This angle can readily be b" 
obtained by trigonometry, or by con- fig.4. 

struction as follows : Construct the right-angle triangle 
ABC to scale. Then the angle ABC can be measured 
with a protractor. The use of this angle will best 
be seen from a few problems. At the equator the 
sun at this time will be directly overhead. Angle 
ABC is 90°, and the complement of this is 0° or the 
latitude. In latitude 5° from the equator the angle 
ABC will be 95°. Applying the same reasoning, 
what is your latitude as determined from angle 
ABC1 Compare this with your latitude as deter- 




10 



MANUAL OF PHYSICAL GEOGRAPHY 



mined by more careful work. The local latitude can 
as easily be obtained at the solstices by adding or sub- 
tracting 23^°. If the angle ABC or the sun's altitude 
is 50° at the equinox, what is the latitude ? If it is 50° 
at the June solstice, what is the latitude ? What is the 
latitude if the sun's altitude is 50° at the December 
solstice ? 

8. REVOLUTION OF THE EARTH 

* Part I. Path of the Earth. — From the following 
table plot a graph of the earth's distance from the sun. 

Table showing the Earth's Distance from the Sun on the 
Fifteenth of Each Month (Derived for 1908) 



Month 


Distance 


Month 


Distance 


Month 


Distance 


January 
February 
March 
April 


9138 X 10* 
9177 X 10* 
9242 X 10* 
9324 X 10* 


May 
June 
July 

August 


9394 X 10* 
9438 X 10' 
9442 X 10* 
9406 X 10* 


September 
October 
November 
December 


9339X 10* 
9259 X 10 4 
9186X10* 
9141X10* 



When is the earth nearest (perihelion) ? When farthest 
(aphelion) ? Is the change from perihelion to aphelion 
sudden or abrupt ? Does the graph show the earth's 
path to be a circle or an ellipse ? If it were a circle, 
how would your graph appear ? What is the average 
distance of the sun ? (Find from your graph, not from 
computation.) What is the range of distances ? (Find 
from your graph.) Preserve your graph. It will be 
needed later. 



THE EABTH AS A PLANET 



11 



Part II. — From the following table plot the average 
daily velocities of the earth for the year. 

Table showing for Each Month the Total Distance in Miles 
Traveled by the Earth in its Orbit and its Average Daily 
Velocity (Calculated for 1908) 



Month 


Miles pek 

Month 


Average 

Daily 
Velocity 


Month 


Miles per 
Month 


Average 

Daily 
Velocity 


January 

February 

March 

April 

May 

June 


50,360,000 
46,910,000 
49,810,000 
47,770,000 
48,980,000 
47,220,000 


1,625,000 
1,618,000 
1,607,000 
1,592,000 
1,580,000 
1,574,000 


July 

August 

September 

October 

November 

December 


48,720,000 
48,940,000 
47,690,000 
49,710,000 
48,440,000 
50,350,000 


1,572,000 
1,579,000 
1,590,000 
1,604,000 
1,615,000 
1,624,000 



Are the velocities equal? How would your graph 
look if they were ? When is the velocity greatest ? 
When least ? Compare your graph with that of Part I. 
Do their maxima and minima come at about the same 
time ? Why ? 

How are the monthly velocity and distance from the 
sun related ? When do the velocities change most sud- 
denly ? Why ? At what parts of the year are the 
velocities least changing ? Why ? How does your 
graph show at a glance the rapid and the slow changes ? 

What is the total length of the earth's path ? In 
what month is it longest ? In what, shortest ? How 
does its length from March to September, inclusive, 
compare with the rest of the year ? 



CHAPTER II 



CLIMATE 



TEMPERATURE 



*9. DIURNAL INSOLATION 



How would you define insolation ? What distinction 
between insolation and temperature ? 

Appaeatus : Take a board twelve inches long and two 
inches wide with the edge at one end sharpened. Nail 
the board to a support, say a piece of plank, with 

the sharp edge uppermost as in 
Figure 5. (Be sure to have the 
upright board at right angles to 
the support.) Turn the appa- 
ratus toward the sun, as in the 
figure, so as to throw a shadow 
of the upright. Measure the 
length of this shadow, ac, each 
hour of the day for as many 
When does the upright not cast a 
At this time is insolation greatest 




Fig. 5. 



days as possible, 
shadow ? Why ? 
or least ? Let several students take the readings and 
take the mean of their readings as the length of the 
shadow. Take temperature readings at the same times. 

12 



CLIMATE — TEMPERATURE 



13 



Plot the temperature readings and the lengths of shadow- 
in two curves. When is the minimum and maximum 
of shadow and of insolation ? Are the shadow lengths 
directly or inversely proportional to the insolations? 
Do the maximum and minimum insolations and tem- 
peratures coincide ? Why ? 

Note. — With such crude apparatus, the insolation readings will not be 
accurate, but will bring out the general facts. It will probably be im- 
possible to get the corresponding readings before and after noon to 
correspond. This experiment is best shown by the " Sun Board." See 
Appendix. 

*10. INSOLATION AT VARIOUS LATITUDES 

The unit is the amount of insolation at the equator, with 
a vertical sun and average distance from the sun. 





80° N. 


80° S. 


60° N. 


60° S. 


40° N. 


40° 8. 


20° N. 


20° 8. 


0° 


January 


0.0 


8.8 


0.1 


13.4 


3.3 


16.6 


9.0 


16.8 


14.0 


February 


0.0 


3.5 


1.0 


9.2 


5.7 


13.9 


11.2 


15.9 


14.9 


March 


0.2 


0.4 


3.9 


4.4 


9.4 


9.9 


13.6 


13.9 


15.3 


April 


2.7 


0.0 


8.2 


1.3 


12.9 


6.0 


15.2 


11.2 


14.6 


May 


7.5 


0.0 


12.0 


0.1 


15.3 


3.4 


15.8 


8.8 


13.5 


June 


10.3 


0.0 


13.8 


0.0 


16.2 


2.4 


15.9 


7.7 


12.8 


July 


8.5 


0.0 


12.6 


0.1 


15.6 


3.0 


15.8 


8.3 


13.1 


August 


3.8 


0.0 


9.2 


0.8 


13.5 


5.2 


15.3 


10.5 


14.2 


September 


0.5 


0.1 


4.9 


3.4 


10.2 


8.8 


14.0 


13.1 


15.0 


October 


0.0 


2.3 


1.5 


7.8 


6.6 


12.8 


11.7 


15.3 


15.0 


November 


0.0 


7.4 


0.2 


12.3 


3.8 


15.9 


9.4 


16.6 


14.2 


December 


0.0 


11.0 


0.0 


14.6 


2.7 


17.3 


8.2 


17.0 


13.6 


Year 


33.5 


33.5 


67.4 


67.4 


115.2 


115.2 


155.1 


155.1 


170.2 



14 MANUAL OF PHYSICAL GEOGRAPHY 

The total insolation north and south of the equator is 
equal, while the distribution of the insolation is unequal. 
What latitudes have no insolation for part of the year ? 
Why? 

From the table, plot on a single sheet the insolations 
for 80° north, 80° south, 60° north, 40° north, 20° 
north, and the equator. Use continuous lines for in- 
solation in north latitudes, and dotted lines for south 
latitudes. Allow ten small squares between each unit 
of insolation so as to allow for decimals. 

What graphs are approximately parallel ? What con- 
trast in graphs for north and for south latitude ? Why ? 
What graph shows the highest insolation ? What 
graph shows the highest average insolation ? How 
do the graphs change in shape as you plot nearer the 
equator ? Do they become the more or the less pointed ? 
What does this change show as to the insolation ? 

How many maxima at the equator ? When do they 
come ? How many do the other graphs show ? Ex- 
plain their contrast in this respect with the graph for 
the equator. Are the maxima at the equator equal ? 
Why? (See Exercise 8, Part I.) From the table 
determine how much greater is the total insolation at 
the equator than at 80° ; than at 40°. Explain why. 
The insolation for a certain month is higher at 40° 
north and 40° south than for the equator. What 
months ? Explain. 



CLIMATE — TEMPERATURE 



15 



11. TABLE SHOWING THE! LENGTH OF DAY IN MINUTES 
AT 60° NORTH LATITUDE, AND THE TEMPERATURE 
AT CHRISTIANIA, NORWAY, LATITUDE 59° 55' 



January 


379 m. 


24.0° 


July 


1066 m. 


62.6° 


February 


531 m. 


23.9° 


August 


927 m. 


60.6° 


March 


690 m. 


34.5° 


September 


763 m. 


52.7° 


April 


858 m. 


39.9° 


October 


600 m. 


41.9° 


May 


1010 m. 


50.9° 


November 


437 m. 


32.1° 


June 


1106 m. 


59.9° 


December 


335 m. 


25.5° 



Plot the insolation from the table in Exercise 10, and 
the length of day and temperature from the above table. 
Are the graphs all parallel ? Are any parallel ? Why ? 
(Give at least two reasons.) Why should the tempera- 
ture lag behind the insolation ? Do both the maximum 
and minimum temperatures lag behind the correspond- 
ing maximum and minimum of insolation ? How does 
the maximum of insolation at 60° north compare with 
that at the equator? How does the minimum at 60° 
north compare with the minimum at 0° ? Which, the 
maximum or the minimum at 60° north, shows the 
greatest contrast with the corresponding phase at the 
equator ? How many hours long is the longest day at 
60° north ? The shortest day ? Is the change of length 
of day gradual or abrupt? When is the most rapid 
change in length of day ? The least rapid change ? 
When is the most rapid change in insolation? The 
least rapid change ? 



16 



MANUAL OF PHYSICAL GEOGBAPHY 



*12. MAXIMA OF TEMPERATURE DUE TO INSOLATION. 
INTERIOR OF AFRICA, LAT. 8° 1' N., LONG. 23.6° E. 



January 


73.4° 


May 


83.7° 


September 


77.7° 


February 


77.2° 


June 


81.5° 


October 


78.1° 


March 


83.8° 


July 


78.8° 


November 


75.7° 


April 


85.3° 


August 


75.7° 


December 


72.9° 



Locate this part of Africa on a general map. Plot 
the temperatures. How many maxima ? When do 
they occur ? How many maxima of insolation on the 
equator ? When do they occur ? How many maxima 
at about 23° north and to the northward ? (See Exer- 
cise 10.) About when do they occur ? What is the 
cause of the maxima on the equator and the maximum 
of 23-|° ? Why are the maxima later here than on the 
equator ? How do the maxima of temperature and of 
insolation near the equator agree ? 



*13. CONTINENTAL AND MARINE AVERAGE ANNUAL 
TEMPERATURES. SAN FRANCISCO AND ST. LOUIS 





San 
Francisco 


St. Louis 




San 
Francisco 


St. Louis 


January 


50 


32 


July 


59 


80 


February 


52 


34 


August 


59 


78 


March 


54 


44 


September 


61 


70 


April 


55 


57 


October 


60 


59 


May 


57 


66 


November 


56 


44 


June 


59 


76 


December 


51 


36 



CLIMATE — TEMPERATURE 



17 



What is the latitude of these cities ? Plot the tem- 
peratures. How much do they differ in range ? Which 
has the warmer summer ? The longer summer ? The 
colder winter? What is the warmest month at San 
Francisco? At St. Louis? Which maximum comes 
sooner ? How would you explain this ? Which has 
the more changeable climate? 

*14. AVERAGE HOURLY TEMPERATURES AT BISMARCK, 
N.D. (ALTITUDE 1681 FEET), AND PORTLAND, ORE. 
(ALTITUDE 157 FEET) 





BlSMAROK 


Portland 




Bismarck 


Portland 


1 A.M. 


36.4 


51.1 


1 P.M. 


45.0 


51.0 


2 A.M. 


35.5 


50.2 


2 P.M. 


46.8 


52.7 


3 A.M. 


34.8 


49.2 


3 P.M. 


48.1 


54.5 


4 A.M. 


34.0 


48.5 


4 P.M. 


48.9 


55.8 


5 A.M. 


33.2 


47.8 


5 P.M. 


49.0 


56.9 


6 A.M. 


32.6 


47.2 


6 P.M. 


48.3 


57.5 


7 A.M. 


32.2 


46.6 


7 P.M. 


46.7 


57.6 


8 A.M. 


33.0 


46.3 


8 P.M. 


44.7 


57.2 


9 A.M. 


34.4 


46.3 


9 P.M. 


42.3 


56.1 


10 A.M. 


37.0 


46.8 


10 P.M. 


40.2 


54.9 


11 A.M. 


40.0 


47.8 


11 P.M. 


38.7 


53.4 


N. 


42.7 


49.2 


M. 


37.4 


52.2 



What is the latitude of these places ? What differ- 
ence in altitude ? 

Plot the temperatures. What is the range of the two 
places ? What difference in ranges ? What is the 



18 



MANUAL OF PHYSICAL GEOGRAPHY 



warmest hour at each place ? What is the coldest ? 
Does the daily graph show the same lag as the monthly 
graph ? (Exercise 13 ) What is the explanation ? 
Which climate is continental ? Which marine ? Give 
complete reasons for your answer. 



15. TEMPERATURES ON THE EAST AND WEST SHORES OF 
OCEANS IN THE BELT OF WESTERLY WINDS 





Phila- 
delphia 


Oppokto 




Phila- 
delphia 


Opporto 


January 


32 


49.2 


August 


74 


69.0 


February 


34 


51.2 


September 


68 


66.7 


March 


40 


54.5 


October 


57 


60.2 


April 


51 


57.0 


November 


45 


53.1 


May 


62 


62.0 


December 


36 


48.5 


June 


72 


65.4 


Year 


54 


58.8 


July 


76 


69.4 









What are the latitudes of Philadelphia and Opporto ? 
What ocean separates them ? How wide is it here ? In 
what climatic zone is this region ? What are the char- 
acteristics of this belt or zone ? What prevalent wind 
directions ? Plot their temperatures. W 7 hich graph 
shows characteristics of a marine climate ? How ? 
Which, a continental climate ? How ? 

Since both places are situated near the ocean, how 
would you explain the fact that one has essentially a 
continental climate ? 



CLIMA TE — TEMPERA TURE 



19 



*16. TEMPERATURE AND ALTITUDE. TEMPERATURES AT 
SPRINGFIELD, ILL. (ALTITUDE 606 FEET), and BRECKEN- 
RIDGE, COL. (ALTITUDE 9524 FEET) 





Springfield 


Breoken- 

RIDGE 




Springfield 


Brecken- 
ridge 


January 


27 


15 


August 


74 


54 


February 


29 


15 


September 


67 


46 


March 


40 


22 


October 


56 


36 


April 


53 


29 


November 


42 


26 


May 


63 


39 


December 


32 


17 


June 


72 


48 


Year 


52 




July 


76 


53 









Locate Springfield, 111. What is its latitude ? 
Breckenridge has about the same latitude. What dif- 
ference in the heights of the two places ? To how 
many miles is this equal ? Plot the temperatures. 
How nearly parallel are the graphs ? How do the 
average annual temperatures compare ? The temper- 
ature ranges ? 



CHAPTER III 

THE MOISTURE OP THE ATMOSPHERE 

*17. WEIGHT OF WATER VAPOR IN A CUBIC FOOT OF 
AIR AT DIFFERENT TEMPERATURES (FAHRENHEIT). 
THE WEIGHT IS EXPRESSED IN TROY GRAINS PER 
CUBIC FOOT OF SATURATED AIR 



-15° 


0.28 


20° 


1.32 


55° 


4.84 


90° 


14.79 


-10° 


0.35 


25° 


1.61 


60° 


5.74 


95° 


17.12 


-5° 


0.45 


30° 


1.95 


65° 


6.78 


100° 


19.76 


0° 


0.56 


35° 


2.36 


70° 


7.98 


105° 


22.75 


5° 


0.70 


40° 


2.84 


75° 


9.35 


110° 


26.11 


10° 


0.87 


45° 


3.41 


80° 


10.93 


115° 


29.88 


15° 


1.07 


50° 


4.07 


85° 


12.73 







Plot the vapor weights and temperatures. (Use only 
the first figure of the decimal.) Do they increase uni- 
formly as the temperature increases ? If they did, what 
kind of a line would your graph be ? At what tempera- 
tures is there the greatest increase in capacity ? The 
least ? From your graph determine approximately the 
capacity of the air of the room in which you are ? 

*18. OBSERVATIONS OF RELATIVE HUMIDITY 

Read the temperature of your thermometer. (Dry- 
bulb reading.) Then wrap about the bulb of your ther- 

20 



THE MOISTURE OF THE ATMOSPHERE 



21 



mometer a bit of thin muslin moistened with water at 
the temperature of the air. Move the thermometer 
about or fan the bulb. Does the mercury rise or fall ? 
Why ? Why is it necessary to keep the air in motion 
around the bulb ? When the mercury becomes station- 
ary, take the reading. (Wet-bulb reading.) 

Subtract the wet-bulb reading from the dry-bulb read- 
ing, and determine the relative humidity from the fol- 
lowing table : — 



Temp. 


Difference between Dry- and Wet-bulb Thermometers 




1 


2 


3 


4 


5 


6 


i 


8 


9 


10 


n 


12 


13 


14 


15 


16 


IT 


IS 


-10 


48 


- 5 


58 


17 





































67 


35 


































5 


74 


48 


22 
































10 


78 


57 


35 


14 






























15 


82 


64 


47 


29 


12 




























20 


85 


70 


56 


41 


27 


13 


























22 


86 


72 


58 


45 


32 


19 


6 
























24 


87 


74 


61 


48 


36 


24 


11 
























26 


88 


75 


63 


51 


40 


28 


17 


6 






















28 


88 


77 


65 


54 


43 


33 


22 


11 


1 




















30 


89 


78 


67 


57 


47 


36 


26 


17 


7 




















32 


90 


79 


69 


59 


50 


40 


31 


21 


12 


3 


















34 


91 


81 


72 


62 


53 


44 


35 


26 


17 


9 


















36 


91 


82 


73 


66 


56 


47 


38 


30 


22 


14 


6 
















38 


92 


83 


75 


67 


58 


50 


42 


34 


26 


18 


1] 


3 














40 


92 


84 


76 


68 


60 


53 


45 


38 


30 


22 


16 


8 


1 












42 


92 


84 


77 


69 


62 


55 


48 


40 


34 


27 


20 


13 


6 












44 


92 


85 


78 


70 


63 


57 


50 


43 


37 


30 


24 


17 


11 


5 










46 


93 


85 


79 


72 


65 


58 


52 


46 


39 


33 


27 


21 


15 


9 


3 









22 



MANUAL OF PHYSICAL GEOGRAPHY 





Difference between Dry- and Wet-bulb Thermometers 


Temp. 




1 


2 


3 


•i 


5 


6 


i 


8 


9 


10 


n 


12 


13 


14 


15 


16 


n 


18 


48 


93 


86 


79 


73 


66 


60 


53 


48 


42 


36 


30 


24 


19 


13 


7 


2 






50 


93 


87 


80 


74 


67 


61 


55 


50 


44 


38 


33 


27 


22 


16 


11 


6 


1 




52 


94 


87 


81 


75 


69 


63 


57 


51 


46 


40 


35 


30 


24 


20 


15 


10 


5 




54 


94 


88 


82 


76 


70 


64 


59 


53 


48 


43 


38 


32 


28 


23 


18 


13 


8 


4 


56 


94 


88 


82 


77 


71 


65 


60 


55 


50 


44 


40 


35 


30 


25 


21 


16 


12 


8 


58 


94 


89 


83 


78 


72 


67 


61 


56 


51 


46 


42 


37 


33 


28 


24 


19 


15 


11 


60 


94 


89 


84 


78 


73 


68 


63 


58 


53 


48 


44 


39 


34 


30 


26 


22 


18 


14 


62 


95 


89 


84 


79 


74 


69 


64 


59 


54 


50 


45 


41 


37 


32 


28 


24 


20 


16 


64 


95 


90 


85 


79 


74 


70 


65 


60 


56 


51 


47 


43 


38 


34 


30 


27 


23 


19 


66 


95 


90 


85 


80 


75 


71 


66 


61 


57 


53 


49 


45 


40 


36 


32 


29 


25 


22 


68 


95 


90 


85 


81 


76 


71 


67 


63 


"58 


54 


50 


46 


42 


38 


34 


31 


27 


24 


70 


95 


90 


86 


81 


77 


72 


68 


64 


60 


55 


52 


48 


44 


40 


36 


33 


29 


26 


72 


95 


91 


86 


82 


77 


73 


69 


65 


61 


57 


53 


49 


45 


42 


38 


35 


31 


28 


74 


95 


91 


86 


82 


78 


74 


70 


66 


62 


58 


54 


50 


47 


43 


40 


36 


33 


30 


76 


95 


91 


87 


82 


78 


74 


70 


66 


63 


59 


55 


52 


48 


45 


41 


38 


35 


31 


78 


96 


91 


87 


83 


79. 


75 


71 


67 


63 


60 


56 


53 


50 


46 


43 


39 


36 


33 


80 


96 


92 


87 


83 


79 


75 


72 


68 


64 


61 


57 


54 


51 


47 


44 


41 


38 


35 


82 


96 


92 


88 


84 


80 


76 


72 


69 


65 


62 


58 


55 


52 


48 


45 


42 


39 


36 


84 


96 


92 


88 


84 


80 


77 


73 


69 


66 


63 


59 


56 


53 


49 


46 


44 


41 


38 


86 


96 


92 


88 


84 


81 


77 


73 


70 


67 


63 


60 


57 


54 


51 


48 


45 


42 


39 


88 


96 


92 


88 


85 


81 


77 


74 


71 


67 


64 


61 


58 


55 


52 


49 


46 


43 


40 


90 


96 


92 


88 


85 


81 


78 


75 


71 


68 


65 


62 


59 


56 


53 


50 


47 


44 


41 


95 


96 


93 


89 


86 


82 


79 


76 


72 


69 


66 


63 


60 


58 


55 


52 


49 


47 


44 


100 


97 


93 


90 


86 


83 


80 


77 


74 


71 


68 


65 


62 


59 


57 


54 


51 


49 


47 


105 


97 


93 


90 


87 


84 


81 


78 


75 


72 


69 


66 


64 


61 


58 


56 


53 


51 


49 



You will note that the left-hand column of figures 
denotes the air temperatures ; the figures across the top 
of the table denote the differences between the dry-bulb 
and wet-bulb thermometers ; the figures below these, in 
the vertical columns, denote the relative humidities at 



THE MOISTURE OF THE ATMOSPHERE 



23 



the given temperatures, and for the given difference be- 
tween the dry-bulb and wet-bulb thermometers. 

For example, if the air temperature is 60° and the 
difference between the dry- and wet-bulb thermometer is 
4°, the relative humidity is 78. Take for your obser- 
vations the readings nearest to those given in the table. 
For example, if your reading is 61. 2° consider it as 61°. 

Have readings taken each hour for several days by the 
class. Plot your readings as in Exercise 19. 



*19. DIURNAL RELATIVE HUMIDITY AT COLUMBIA, MO., 
JULY 25, 1908. WINDS VERY LIGHT 





T. 


E.H. 


Sky 


Wind 


5 A.M. 


74 


82 


Clear 


S.E. 


6 A.M. 


76 


76 


Sunny 


S.E. 


7 a.m. 


75 


82 


Cloudy 


S.E. 


8 a.m. 


78 


79 


Sunny 


S.E. 


9 a.m. 


79 


75 


Sunny 


S.E. 


10 a.m. 


81 


72 


Cloudy 


S.E. 


11 A.M. 


83 


69 


Sunny 


S.E. 


N. 


83 


69 


Sunny 


S.E. 


1 P.M. 


87 


60 


Sunny 


S.E. 


2 P.M. 


87 


60 


Sunny 


S.E. 


3 P.M. 


87 


62 


Sunny 


S.E. 


4 P.M. 


86 


63 


Cloudy 


S.E. 


5 P.M. 


86 


65 


Sunny 


S.E. 


6 P.M. 


84 


66 


Sunny 


S.E. 


7 P.M. 


82 


69 


Cloudy 


S.E. 


8 P.M. 


81 


72 


Clear 


S.E. 


9 P.M. 


80 


79 


Clear 


S.E. 


10 P.M. 


78 


83 


Clear 


S.E. 



24 



MANUAL OF PHYSICAL GEOGBAPHY 



Plot the temperatures, placing the hours on the long 
side of the sheet and the temperatures on the narrow 
side. Plot the relative humidities on the same sheet, 
placing the graph below that for temperature. Are 
your graphs parallel ? Explain the reasons for your 
answer. Which graph is most irregular ? What reasons 
can you give for this ? 

Plot also on the same sheet the absolute humidity 
as given in Exercise 17. 



20. TEMPERATURE, ABSOLUTE HUMIDITY, AND RELA- 
TIVE HUMIDITY AT KEY WEST, FLA., AND SALT LAKE 
CITY, UTAH 



(Th 


3 absolute humidity is 


given in troy grains 


per cubic foot.) 






Key West 


Salt Lake 
City 




Key West 


Salt Lake 
City 


t. 


A. II. 


K.H. 


t. 


A. II. 


R.n. 


t. 


A. II. 


R.H. 


t. 


A.H. 


R.H. 


January- 


70 


6.00 


81 


28 


1.34 


75 


August 


84 


8.88 


74 


75 


3.05 


35 


February 


71 


6.24 


79 


33 


1.47 


70 


September 


85 


8.87 


77 


64 


2.46 


38 


March 


73 


6.36 


76 


42 


1.62 


59 


October 


79 


8.18 


78 


52 


2.14 


51 


April 


76 


6.62 


73 


50 


1.88 


48 


November 


74 


7.09 


79 


40 


1.80 


62 


May 


79 


7.55 


74 


58 


2.46 


47 


December 


70 


6.32 


80 


33 


1.48 


72 


June 


82 


7.60 


77 


67 


2.65 


38 


Year 


77 


7.47 


77 


52 


2.24 


52 


July 


84 


8.75 


74 


76 


2.97 


34 

















Plot, if possible, on the same sheet of paper, the tem- 
peratures, absolute humidities, and relative humidities 
for Key West and Salt Lake City. (If the paper is 
large enough, allow the first eight squares to represent 



THE MOISTURE OF THE ATMOSPHERE 



25 



temperatures, the next eight to represent absolute humid- 
ities, and the next six to represent relative humidities.) 

What graphs are most nearly parallel ? What graphs 
have opposite directions ? Which graphs show values 
that vary directly ? Which, inversely ? How would 
you explain these facts ? How do your conclusions 
compare with those derived in Exercise 19? 

From the temperatures, which climate would you in- 
fer has continental characteristics ? What are these 
characteristics ? Which marine ? What characteristics ? 
How would you describe the relative and absolute hu- 
midities in continental and marine climates as to amount, 
range, and distribution ? 

21. CLIMATE DURING AUGUST, 1896 





Boston 


Philadelphia 


St. Louis 


Denver 


T. 8 A.M. 


69 


72 


72 


60 


T. 8 p.m. 


70 


77 


82 


79 


Max. Temp. 


78 


85 


88 


85 


Av. August 


70 


76 


79 


71 


R.H.8a.m. 


73 


70 


78 


60 


R.H.8p.m. 


74 


62 


61 


31 



During August, 1896, in the Eastern and interior 
cities, there were thousands of cases of sunstroke and 
heat prostrations, while the cities of the Great Basin 
and Rocky Mountain region were fairly comfortable. 



26 



MANUAL OF PHYSICAL GEOGRAPHY 



Analyze the table given above and determine what dif- 
ference in climatic factors there were between Denver 
and the Eastern cities. 

*22. EQUATORIAL RAINFALL. QUITO (In inches) 



January 

February 

March 


3.2 
6.4 
4.4 


April 

May 

June 


6.6 
5.1 
2.5 


July 

August 
September 


1.4 

1.8 
1.8 


October 

November 

December 


4.4 
6.2 

2.8 



Where is Quito? What is its latitude? Plot the 
rainfall. How does the graph compare with that for 
insolation ? (Exercise 10.) How many maxima are 
there ? How many minima ? Do the maxima coin- 
cide with the maxima of insolation ? (See Exercise 10.) 
Do they precede or follow them ? What are the rainy 
months ? The dry months ? What is the annual rain- 
fall ? What percentage of this falls in the rainy sea- 
sons ? Is the transition from rainy to drier seasons 
gradual or abrupt ? 



*23. TROPICAL RAJNFALL. MEXICO (In inches) 



January 

February 

March 


0.15 
0.19 
0.59 


April 

May 

June 


0.59 
2.00 
4.09 


July 

August 
September 


4.09 

4.84 
4.13 


October 

November 

December 


1.69 
0.43 
0.15 



What is the latitude of Mexico? Plot its rainfall. 
When does the maximum come ? When the minimum ? 



THE MOISTURE OF THE ATMOSPHERE 



27 



When is the maximum of' insolation at about that lati- 
tude ? (See Exercise 10.) What relation between the 
maxima of rainfall and of insolation ? What is the 
reason for this ? Does the maximum rainfall precede 
or follow the maximum insolation ? Explain. W'hat 
are the rainy months ? The dry months ? 



24. MONSOONAL TYPE OF RAINFALL (In inches). 
RAPUNJI, INDIA, LAT. 25° N. 



CHER- 



January 

February 

March 


0.8 

2.8 
8.8 


April 

May 

June 


30.9 

51.4 

115.9 


July 

August 

September 


130.8 
79.6 
56.1 


October 

November 

December 


13.7 
2.2 
0.2 



What is a monsoon ? What is its origin ? Plot the 
rainfall. What is the total rainfall ? When is the 
maximum ? Does this maximum coincide with the 
maximum insolation ? When is the minimum ? What 
months are rainy ? What dry ? 



CHAPTER IV 

CYCLONES AND ANTICYCLONES 
*25. GENERAL MAP STUDY OF A CYCLONE 

Where is the center of the cyclone ? What does the 
word low mean ? What is the pressure at the cen- 
ter ? How is pressure indicated ? What does the word 
isobar mean ? How does the pressure change as you go 
from the " low " outward ? As you go toward the 
" low " ? Roughly, what is the shape of the cyclone 
area ? What is its approximate area ? 

In general, which wa} 7 do the winds blow — ■ to or 
from the center ? Why ? Do they blow straight into 
the center ? What is the average wind velocity of ten 
places near, but not in, the center of the cyclone ? Of 
ten places near the periphery of the cyclone ? What is 
the general direction of winds in the easterly part of the 
cyclone ? The westerly part ? 

How are temperatures shown ? What is the mean- 
ing of the word isotherm f Do the isotherms go east 
and west across the cyclone ? 

How are states of sky shown : Rain ? Snow ? 
Thunderstorms ? What information is given in the 
table that is not given in the weather map ? 

28 



CYCLONES AND ANTICYCLONES 



29 



GENERAL STUDY OF AN ANTICYCLONE 

Take up the same points in the study of a good anti- 
cyclone that you considered in the cyclone. 

*26. CONSTRUCTION OF A WEATHER MAP 





Pressure 


Temper- 
ature 


Wind 

Direction 


Wind 
Velocity 


Sky 


Escanaba, Mich. 


28.9 




N. 


14 


Snow 


Green Bay, Wis. 


28.9 


30 


N.W. 


22 


Cloudy 


Marquette, Wis. 


29.0 




N.W. 


20 


Snow 


La Crosse, Wis. 


29.0 




N. 




Snow 


Milwaukee, Wis. 


29.0 




N.W. 


16 


Cloudy 


Grand Rapids, Mich. 


29.0 




s.w. 


30 


Snow 


Alpena, Mich. 


29.0 




s.w. 


14 


Cloudy 


Houghton, Mich. 


29.1 




N. 


18 


Snow 


Dubuque, la. 


29.1 




N.W. 


14 


Snow 


Chicago, 111. 


29.1 




S.W. 


24 


Cloudy 


Detroit, Mich. 


29.1 




s.w. 


14 


Cloudy 


Saugeen, Can. 


29.1 


30 


s. 




Cloudy 


White River, Can. 


29.2 


20 








Des Moines, la. 


29.2 




N.W. 


12 


Snow 


Peoria, 111. 


29.2 










Sandusky, Ohio 


29.2 


40 


S.W. 




Cloudy 


Buffalo, N.Y. 


29.2 




s.w. 


24 


Cloudy 


Duluth, Minn. 


29.3 


20 


N.W. 




Cloudy 


St. Paul, Minn. 


29.3 




N.W. 


24 


Cloudy 


Keokuk, la. 


29.3 


20 


S.W. 


14 


Cloudy 


Pittsburg, Pa. 


29.3 


40 


W. 


14 


Cloudy 


Scranton, Pa. 


29.3 


40 


N.W. 


6 


Cloudy 


Oswego, N.Y. 


29.3 


30 


S. 


10 


Rain 


Rockcliffe, Can. 


29.3 


20 


N.E. 





Cloudy 


Omaha, Neb. 


29.4 


20 


N.W. 


14 


Clear 


St. Louis, Mo. 


29.4 


30 


W. 


28 


Cloudy 



30 



MANUAL OF PHYSICAL GEOGRAPHY 





Pressure 


Temper- 


Wind 


Wind 


Sky 






ature 


Direction 


Velocity 




Cincinnati, Ohio 


29.4 


40 


s.w. 


16 




Elkins, W. Va. 


29.4 




w. 


6 


Rain 


Richmond, Va. 


29.4 


50 


s.w. 


30 


Cloudy 


Atlantic City, N. J. 


29.4 




s.w. 


20 


Cloudy 


Block Island, R.I. 


29.4 


50 


s. 


22 


Rain 


Albany, N.Y. 


29.4 




N.E. 


6 


Rain 


Cape Henry, Va. 


29.5 




S. 




Cloudy 


Wytheville, Va. 


' 29.5 




w. 


16 


Cloudy 


Lexington, Ky. 


29.5 




s.w. 


28 


Cloudy 


Columbia, Mo. 


29.5 










Moorehead, Minn. 


29.6 




N. . 


8 


Clear 


Devils Lake, N.D. 


29:6 


20 


N.W. 


4 


Cloudy 


Yankton, S.D. 


29.6 




N.W. 




Cloudy 


Kansas City, Mo. 


29.6 




W. 


10 


Clear 


Springfield, Mo. 


29.6 


30 


w. 


12 


Clear 


Nashville, Tenn. 


29.6 


40 


s.w. 


14 


Clear 


Wilmington, N.C. 


29.6 




w. 


14 


Cloudy 


Boston, Mass. 


29.6 


40 


S.E. 


6 


Cloudy 


Northfield, Vt. 


29.6 


30 


S. 


8 


Cloudy 


Charleston, S.C. 


29.7 




S.W. 


12 


Rain 


Atlanta, Ga. 


29.7 




S.W. 


14 


Clear 


Little Rock, Ark. 


29.7 




s.w. 


8 


Clear 


Oklahoma, Ok. 




30 


w. 




Cloudy 


Dodge, Kan. 


29.7 




N.W. 




Cloudy 


Minnedosa, Can. 


29.7 




w. 




Cloudy 


Havre, Mont. 


29.8 




s.w. 


26 


Clear 


Williston, N.D. 


29.8 




s.w. 


Lt. 


Clear 


Pierre, S.D. 


29.8 




N.W. 


18 


Cloudy 


Amarillo, Tex. 


29.8 




w. 


24 


Snow 


Vicksburg, Miss. 


29.8 


40 


s.w. 


10 


Cloudy 


Montgomery, Ala. 


29.8 




w. 


12 


Cloudy 


Tampa, Fla. 


29.8 


60 


N.W. 


Lt. 


Rain 


Key West, Fla. 


29.9 


70 


s. 


8 


Cloudy 


New Orleans, La. 


29.9 


40 


N.W. 


10 


Cloudy 



CYCLONES AND ANTICYCLONES 



31 





Pressure 


Temper- 
ature 


Wind 
Direction 


Wind 
Velocity 


Sky 


Abilene, Tex. 


29.9 


30 


s.w. 


6 


Cloudy 


Denver, Col. 


29.9 


30 


N.W. 


18 


Cloudy 


Miles City, Mont. 


29.9 




S.W. 


Lt. 


Clear 


Kamloops, Can. 


29.9 


30 


S.E. 


Lt. 


Clear 


Cheyenne, Wyo. 


30.0 




N.W. 


36 


Cloudy 


Roswell, N.M. 


30.0 




W. 


Lt. 


Clear 


Galveston, Tex. 


30.0 




w. 


8 


Cloudy 


Sante Fe, N.M. 


30.1 


20 


.N.E. 


16 


Clear 


Helena, Mont. 


30.1 




W. 


Lt. 


Cloudy 


Kalispel, Mont. 


30.1 




N.W. 


Lt. 


Clear 


Victoria, Can. 


30.1 


40 


E. 


Lt. 


Snow 


Tacoma, Wash. 


30.2 


40 


S. 


8 


Cloudy 


Spokane, Wash. 


30.2 


30 


N.E. 


8 


Cloudy 


Lander, Wyo. 


30.2 


20 


N. 


Lt, 


Clear 


El Paso, Tex. 


30.2 




W. 




Clear 


Portland, Ore. 


30.3 


40 


S.E. 


Lt. 


Cloudy 


Baker City, Ore. 


30.3 


20 


S.E. 


Lt. 


Clear 


Grand Junction, Col. 


30.3 


20 


N. 


Lt. 


Clear 


Durango, Col. 


30.3 





N. 


Lt. 


Clear 


Flagstaff, Ariz. 


30.3 


10 


E. 


Lt. 


Clear 


Winnemucca, Nev. 




10 


N.E. 


Lt. 


Clear 


Independence, Cal. 


30.3 


30 




10 


Clear 


San Francisco, Cal. 


30.3 


40 


N. 


Lt. 


Clear 


Roseburg, Ore. 


30.4 


40 


S. 


Lt. 


Cloudy 


Boise, Id. 


30.4 




N.W. 


Lt. 


Cloudy 


Salt Lake City, Utah 


30.4 




N.E. 





Cloudy 


Modena, Utah 


30.4 











Sacramento, Cal. 


30.4 


30 


N.W. 


6 


Clear 


Red Bluff, Cal. 


30.4 


30 


N. 


Lt. 


Clear 



On a blank weather map (form DD), sketch in the 
isobars (continuous lines). What is the lowest pressure ? 
Where is it ? The highest pressure ? Where is it ? 



32 MANUAL OF PHYSICAL GEOGRAPHY 

Where is there a cyclone ? What states does it cover ? 
An anticyclone ? What states covered ? Where are 
the isobars close together ? Where farthest apart ? 
Are the isobars closer near the center or near the margin 
of the cyclone ? In going in a direction across the 
isobars, where would you find the most rapid change in 
pressure, where the isobars are close or far apart ? The 
rate of change is expressed by the pressure gradient, i.e. 
the change per latitude degree (about 70 miles in this 
latitude). The formula for determining the pressure or 
barometric gradient is 

t> , . n j. , Difference in Pressure 

.Barometric Gradient = — — — — . 

Difference m Distance 

70 miles 

As nearly as possible, the measurements must be taken 
perpendicular to the isotherms. 

What is the barometric gradient between Chicago 
and Springfield, Mo. ? Between Chicago and Nashville, 
Tenn. ? Between Portland, Ore., and Tacoma, Wash. ? 

At each station where wind direction is given, draw 
an arrow, with the point showing the way the wind is 
blowing. How do they blow with, reference to the 
cyclone and the anticyclone ? Do they blow directly 
into or away from either ? Do they blow at right 
angles to the isobars ? 

On a separate map, write the wind velocities at the 



CYCLONES AND ANTICYCLONES 33 

different stations. Compare the velocities in the 
cyclonic and the anticyclonic regions ; the inner and 
the outer portions of the cyclone. Select ten stations 
in the cyclonic region where the isobars are close to- 
gether and find the average wind velocity. Also ten 
stations where the isobars are farthest apart. How do 
the velocities in the two groups of stations compare ? 

On the first map draw isotherms ; i.e. connect with a 
line all points having the same temperature, first writ- 
ing the temperatures at the different stations. Where 
is the coldest locality ? The warmest ? What is the 
general trend of the isotherms east of the Rocky 
Mountains ? Do isotherms on the average run east- 
west or north-south ? How can the behavior of these 
isotherms be explained by wind direction ? How would 
you explain the fact that New Orleans has the same 
temperature as Buffalo ? Where do the isotherms make 
closed lines ? Which is the warmer, the center of the 
cyclone or of the anticyclone ? 

On the first map, mark your arrows to show the state 
of sky. (See the symbols in the lower left-hand corner 
of a weather map.) How does the state of sky in the 
cyclone and the anticyclone compare ? Where is it 
freezing ? Where is it clear ? Where, cloudy ? Where 
is it raining? Where, snowing? Where are the winds 
light? Where are there strong winds? What is the 
season, summer or winter ? Why do you think so ? 



34 MANUAL OF PHYSICAL GEOGBAPHY 

*27. WIND DIRECTIONS IN CYCLONES AND ANTI- 
CYCLONES 

Take a piece of tracing paper about six inches square. 
Draw a line from the middle of one side through the 
center, and draw a line at right angles to the first line 
and through the center of the sheet. Your sheet will 
be divided into four equal parts. Find a well-marked 
cyclone, place the intersection of the lines over the cen- 
ter of the cyclone, and copy the wind arrows of the 
cyclone. Do this for several cyclones and you will 
have a composite picture of wind directions in a cyclone. 
What is the general wind direction in each quadrant 

of the cyclone? On a 
separate sheet make a 
wind diagram for each 

^ quadrant as follows : 

find the number of 
winds from north, 

Fig. 6. ' 

northeast, east, south- 
east, south, southwest, west, northwest. From a point, 
draw arrows in the various directions whose lengths 
are proportional to the numbers of winds. For 
example, suppose there are 10 winds from the north, 
20 winds from the east, 15 winds from the west, 
and 5 winds from the south. The diagram will 
appear as in Figure 6. Do the winds enter the 
cyclone directly or spirally? Where is the "low" 



CYCLONES AND ANTICYCLONES 35 

with reference to a south wind ? A southeast wind ? 
An east wind ? A northeast wind ? A west wind ? 
Explain the reason for the " wind-barometer indica- 
tions " found on the weather maps. 

Work out in a similar manner the wind directions 
around a series of well marked anticyclones. 

*28. ISOTHERMS IN CYCLONES AND ANTICYCLONES 

Copy the isotherms in several well-marked cyclones 
and anticyclones on the same blank map. Do the iso- 
therms pass through a cyclone in an east-west direction ? 
Latitude alone considered, what would be the direction 
of the isotherms ? Draw a generalized isotherm that 
will show the average directions of all your isotherms. 
How does the isotherm behave in passing from an anti- 
cyclone to a cyclone ? How in passing through a cyclone? 
How are the curves of the isotherms correlated with wind 
directions ? 

*29. STATE OF SKY IN CYCLONES AND ANTICYCLONES 

Following the same method, as in Exercise 27, study 
several well-marked cyclones and anticyclones east of the 
Rocky Mountains. Put a circle for clear sky, a shaded 
circle for cloudy sky, R. for rain, and S. for snow. 
You will thereby obtain a picture of the sky conditions 
in a cyclone and anticyclone. In general, how do 
the front and rear (east and west sides) of a cyclone 



36 



MANUAL OF PHYSICAL GEOGRAPHY 



compare ? Which winds are usually associated with 
cloudiness ? Why ? Which winds usually bring clear- 
ing weather ? Why ? What is the usual state of sky 
in and around an anticyclone ? 



30. INFERENCE OF A CYCLONE OR ANTICYCLONE FROM 
WIND DIRECTION 





Direction 


Velocity 


Duluth, Minn. 


E. 


16 


Marquette, Mich. 


N.E. 


8 


St. Paul, Minn. 


E. 


10 


Sioux City, la. 


E. 


22 


Chicago, 111. 


E. 


26 


Kansas City, Mo. 


E. 


14 


Springfield, 111. 


N.E. 


14 


Grand Rapids, Mich. 


N.E. 


4 


Detroit, Mich. 


N. 


14 


Indianapolis, Ind. 


N.E. 


8 


Knoxville, Tenn. 


N.E. 


4 


Cairo, 111. 


N.E. 


8 


Elkins, W.Va. 


N. 


6 


Washington, D.C. 


N. 


16 


Philadelphia, Pa. 


N.W. 


12 


Buffalo, N.Y. 


N.W. 


16 


Albany, N.Y. 


N.W. 


12 


Boston, Mass. 


W. 


14 


Northfield, Vt. 


N.W. 


14 


Parry Sound, Ont. 


W. 


8 


Eastport, Me. 


w. 


26 


Father Point, Quebec 


s.w. 


28 



Indicate by arrows on a blank weather map the wind 
direction at the different stations. Are the winds due 



CYCLONES AND ANTICYCLONES 



37 



to a cyclone or to an anticyclone ? Fully state the 
reasons for your answer. Where is the center of the 
wind movement ? Do the winds blow straight from 
this center ? Which way are they deflected ? Why? 

Compare the wind average velocities in three locali- 
ties : west of Lake Michigan, south of Lake Michigan 
and Erie, and southeast of Lakes Erie and Ontario. 

What is the average of wind velocity in each group ? 
Where do you think the barometric gradients are steep- 
est ? Least steep ? What relation between the gradients 
and wind velocities? 



31. INFERENCE OF CYCLONES AND ANTICYCLONES 
FROM ISOTHERMS 

On a blank weather map, draw isotherms according 
to the following table : — 



San Diego, Cal. 


50° 


Del Rio, Tex. 


60° 


El Paso, Tex. 


50° 


Winnemucca, Nev. 


40° 


Abilene, Tex. 


50° 


Flagstaff, Ariz. 


40° 


Fort Smith, Ark. 


50° 


Roswell, N.M. 


40° 


Chicago, 111. 


50° 


Topeka, Kan. 


40° 


Detroit, Mich. 


50° 


St. Paul, Minn. 


40° 


Albany, N.Y. 


50° 


Devils Lake, N.D. 


40° 


Boston, Mass. 


50° 


Havre, Mont. 


40° 


Cape Henry, Va. 


60° 


Salt Lake City, Utah 


40° 


Wytheville, Va. 


60° 


Denver, Col. 


30° 


Indianapolis, Ind. 


60° 


North Platte, Neb. 


30° 


Little Rock, Ark. 


60° 


Valentine, Neb. 


30° 


Palestine, Tex. 


60° 


Cheyenne, Wyo. 


30° 



38 MANUAL OF PHYSICAL GEOGRAPHY 

What isotherms make closed lines ? Which extend 
entirely across the continent ? From your previous 
studies, where would you infer there is a cyclone ? 
Why ? An anticyclone ? Why ? 

Temperature gradients are found in the same man- 
ner as barometric gradients. Where are the tempera- 
ture gradients steep in this map? Where gentle? 
What is the temperature gradient between Chicago 
and Indianapolis ? Between Buffalo and Cape Henry, 
Va.? What do you think is the prevailing wind 
direction in Georgia ? In Minnesota ? 

32. CONDITIONS IN" DIFFERENT PARTS OF CYCLONES 
AND ANTICYCLONES 

From March 1 to March 5, 1904, a cyclone followed 
by an anticyclone passed across the United States. 
The center of the cyclone was near North Platte, 
Neb., March 2 ; Buffalo, N.Y., March 3 ; and Halifax, 
N.S., March 4. The center of the anticyclone was 
n^ar Eureka, Cal., March 2 ; Dodge, Kan., March 3 ; 
Indianapolis, Ind., March 4; and Eastport, Me., March 5. 
Indicate by a continuous line on a blank weather map 
the path of the cyclone center, writing the dates for the 
center at the proper stations. Show by a dotted line 
the path of the anticyclone and write the dates for its 
center. What is the average hourly rate of the cy- 
clone's progress ? Of the anticyclone ? 



CYCLONES AND ANTICYCLONES 



39 



The following tables give data for three stations : 
one near the paths of the centers, one to the north, and 
one to the south of these paths : — 





Pressure 


Temperature 


March 2 


March 3 


March 4 


March 2 


March 3 


March 4 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


St. Paul 
St. Louis 
New Orleans 


28.7 
29.2 
30.0 


28.9 
28.9 
29.9 


29.4 
29.6 
29.9 


29.4 
29.8 
30.1 


29.4 
29.8 
30.2 


29.1 
29.6 
30.1 


32 

42 
67 


12 
69 

72 


-2 
22 
66 


21 
30 
55 


4 
26 
40 


28 
37 
54 





Wind Direction 


State of Sky 1 


March 2 


March 3 


March 4 


March 2 


March 3 


March 4 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 


P.M. 


A.M. 

1 





P.M. 

10 
3 



St. Paul 
St. Louis 
New Orleans 


E. 
S.E. 
S.W. 


N.W. 

s. 
s. 


N.W. 

N. 
S. 


N.W. 

N.W. 
N. 


E. 

S. 
N.E. 


S.E. 
S.E. 
S.E. 


10 
5 

9 


10 
2 

8 



4 
2 






10 



Draw graphs showing the pressures at the three 
stations. Which station shows the greatest pressure 
range ? Why ? How does the graph show the ap- 
proach and recession of the cyclone at St. Louis ? Why, 
at each station, is the pressure greater on March 4 than 
on March 2 ? 

1 In tenths of cloudiness; indicates a clear sky, 10 a sky covered by 
clouds. 



40 



MANUAL OF PHYSICAL GEOGRAPHY 




Draw graphs showing the temperatures at the three 
stations. (Place the dates about four large squares 
apart so that the graphs will extend well across the 
page.) Which graphs are most nearly parallel ? 

Write the wind directions along the temperature 
graphs at the proper places. What winds caused a rising 
temperature ? A falling temperature ? 

At each station 
show, the wind direc- 
tions as in Figure 7. 
At which station is 
there no south wind ? 
Why? Why do the 
winds at St. Paul 
"back" from easterly 
to westerly winds? 
Why is there a south- 
easterly wind at St. 
Paul on the afternoon of March 4 ? Account for the 
winds at St. Louis. The winds of St. Louis on the 
afternoon of March 4 were caused by another cyclone. 
Where was its position ? What is the predominating 
wind direction at New Orleans ? How would you 
explain the northerly winds here ? 

In general, what winds at St. Paul and St. Louis give 
a clear sky ? 



MAR. 2, A.M. 



MAR. 4, A.M. 




Fig. 7. 



CYCLONES AND ANTICYCLONES 41 

33. CYCLONES AND ANTICYCLONES IN SUMMER AND IN 

WINTER 

Look over several maps, both summer and winter. 
In which season do you find the cyclones and anti- 
cyclones best developed ? What is the state of sky in 
front and rear of the cyclone in most of them ? How 
does this compare with the anticyclone ? In what part 
of the cyclone is rain most frequent in New England ? 
In the Mississippi Valley ? 

In the winter cyclone from which part does a " cold 
wave" come most frequently? Find an anticyclone 
that produces a " cold wave." Do they usually produce 
a cold wave ? In which, a cyclone or an anticyclone, 
are the barometric gradients usually steepest ? In 
which are the winds usually highest, a cyclone or an 
anticyclone ? Sketch a good example of a cyclone and 
anticyclone which produce cold waves. 

Do the summer cyclones and anticyclones move faster 
or slower than in winter ? In your locality which part 
of the cyclone brings cool weather ? What kind of 
weather does an anticyclone bring ? Find a period 
where there are practically no cyclones or anticyclones. 
What is the weather : quiet or windy ? hot or cold ? 
pleasant or oppressive ? cloudy or clear ? Is the rain- 
fall, if any, general or local ? Write a brief report on 
the above conditions specifying dates, places, and con- 
ditions. 



42 MANUAL OF PHYSICAL GEOGRAPHY 

*34. CYCLONE PATHS 

If weather maps for one year, or for several years, are 
available, let each student trace the cyclones for one 
month. Follow each cyclone across the map and show 
the path of the cyclone center by a line. Then assemble 
the maps and draw: (a) the average annual cyclone 
path, (b) the average summer cyclone path, (c) the 
average winter cyclone path. 

Which is the most northerly path, that for summer 
or winter ? Where do cyclones usually leave the United 
States ? About what percentage come from the north- 
west ? From the southwest ? 

How would the climate be changed if the average 
cyclone path were east-west at about the latitude of 
Memphis, Tenn.? How if it were east-west through 
New Orleans ? 



CHAPTER V 

MISCELLANEOUS CLIMATIC PHENOMENA 

*35. A LAND AND SEA BREEZE. BOSTON, MASS. 
JUNE 27, 1908 





Wind 
Direction 


Temperature 




"Wind 
Direction 


Temperature 


1 A.M. 


w. 


63 


1 P.M. 


E. 


72 


2 A.M. 


w. 


62 


2 p.m. 


E. 


70 


3 A.M. 


w. 


62 


3 p.m. 


E. 


71 


4 A.M. 


w. 


62 


4 P.M. 


E. 


73 


5 A.M. 


w. 


61 


5 P.M. 


S.E. 


75 


6 A.M. 


w. 


62 


6 P.M. 


S.E. 


75 


7 A.M. 


N.W. 


66 


7 P.M. 


S.E. 


74 


8 A.M. 


E. 


69 


8 P.M. 


S. 


72 


9 A.M. 


S.E. 


73 


9 P.M. 


s. 


69 


10 A.M. 


E. 


74 


10 P.M. 


s.w. 


68 


11 A.M. 


E. 


75 


11 P.M. 


s.w. 


68 


12 N. 


E. 


72 


12 m. 


s.w. 


67 



Plot the temperatures. About an inch above your 
graph, write the wind directions for each hour. When 
did the sea breeze begin ? How long did it continue ? 
Why did it blow during this time ? When did the land 
breeze begin ? How long did it continue ? What is the 
reason for its occurence ? 



43 



44 MANUAL OF PHYSICAL GEOGRAPHY 

If the temperature were due to insolation alone, when 
would its maximum come ? How does your graph com- 
pare with those in Exercise 14? How has the sea breeze 
modified the usual graph for daily temperature ? With- 
out the sea breeze how would the temperature graph for 
Boston probably appear ? 

36. A CHINOOK WIND 
Denver, Col., Quadrangle 

On February 9, 1909, a well-marked chinook wind 
blew at Denver, Col. There was an area of high pres- 
sure in Arizona and an area of low pressure in eastern 
Colorado. The following table gives the temperatures, 
wind directions, and relative humidities at Denver on 
that day. On a blank weather map, indicate the loca- 
tions of high- and low-pressure areas. 

How is Denver situated with reference to the Rocky 
Mountains ? Plot the temperatures. When is there a 
rise ? How much of a rise ? What change in wind 
direction nearly coincides with this rise ? Does this 
wind direction usually produce a rise in temperature ? 
Explain how it does in this case. How does the rela- 
tive humidity change during the chinook ? Explain 
this. How would the relative positions of the areas of 
low and of high pressure cause a chinook ? How would 
the location of Denver favor a chinook ? Would you 
think that chinooks are desirable in winter ? Why ? 



MISCELLANEOUS CLIMATIC PHENOMENA 



45 





Temperature 


Wind 




Temperature 


"Wind 


1 A.M. 


1 


S.E. 


1 P.M. 


29 


N.W. 


2 A.M. 


1 


S.E. 


2 P.M. 


32 


N.W. 


3 A.M. 





S.E. 


3 P.M. 


30 


N.W. 


4 a.m. 


1 


S. 


4 p.m. 


30 


N.W. 


5 A.M. 


1 


S. 


5 P.M. 


28 


N.W. 


6 A.M. 


2 


S.W. 


6 P.M. 


28 


N.W. 


7 A.M. 


2 


S.W. 


7 P.M. 


28 


N.W 


8 A.M. 


3 


s.w. 


8 P.M. 


27 


N.W. 


9 a.m. 


14 


s.w. 


9 P.M. 


27 


N.W. 


10 a.m. 


28 


s. 


10 P.M. 


26 


N.W. 


11 A.M. 


31 


N.W. 


11 P.M. 


26 


W. 


12 N. 


30 


N.W. 


12 m. 


28 


W. 




Relati 


ve humidit. 


y a.m. 92; p.m. 48. 





*37. OBSERVATION OF A RAIN STORM 

Date and hour ? Direction and velocity of the wind? 
Is the storm evidently in a cyclone or an anticyclone, 
or is it local? What kind of clouds preceded the 
storm? What change, if any, took place in the clouds 
preceding and during the storm ? How long did the 
rain last? Was it followed by a clearing sky? Were 
the drops large or small ? Was there any difference in 
size of the drops at the beginning and at the end of the 
storm ? Was it cooler or warmer during the storm ? 
After the storm ? How much rain fell ? If possible, 
compare a summer and a winter rain storm in all the 
particulars noted above. 



46 MANUAL OF PHYSICAL GEOGRAPHY 

38. THE PEW-POINT 

Take a bright tin cup. Fill with water at the tem- 
perature of the room. Put in a lump of ice and stir the 
water with the thermometer (be careful not to break 
the thermometer), watch carefully the surface of the cup, 
and record the temperature of the water at which mois- 
ture first collects on the outside of the cup. This is 
the dew-point. Why ? 

39. OBSERVATIONS UPON DEW DEPOSITION 

Dew : Quantity (heavy or light) . — Several leaves or 
blades of grass may be collected and weighed. After 
drying, they can be weighed again, and the difference in 
weights will show approximately the amount of dew. 
This weight can be reduced to inches or fractions of an 
inch. One cubic inch of water weighs about half an 
ounce. Care should be taken not to shake off any of 
the dew or to allow the plants to wilt. Note the things 
upon which dew collects (wood, stone, different plants, 
etc.). Temperature the night before. State of sky, 
movement of air. How long before the dew disappears 
in the morning. See if this has any relation to the air 
movements, the temperature, and the relative humidity. 
Place of observation (level or hilly ; exposure in what 
direction; proximity of houses, trees, etc.). It would 
be interesting to compare the amount of dew, and the 



MISCELLANEOUS CLIMATIC PHENOMENA 47 

rapidity of disappearance in a grove or forest and an 
open space. 

40. STUDY OF A FOG 

What is fog? What is its general cause? Where 
have you seen it occur ? If over land or water, what is 
the apparent cause ? How dense is it ? (This is 
usually estimated by the distance one can see through 
the fog.) Does it disappear suddenly or slowly ? Find 
out, if possible, at what time the fog began to appear. 
If you can see the upper part of the fog, estimate how 
thick it is. Does it occur in a valley or on a hill, or 
both ? If possible take temperature readings to deter- 
mine at what temperature it disappears, and if the tem- 
perature changes suddenly at the disappearance of the 
fog. Relative humidity readings would be interesting. 
Did you ever see a fog around a piece of ice or a water 
pitcher on a hot day? Explain. What effect has the 
fog on bodily sensations ? On business (e.g. the fogs of 
London) ? 

*41. CLOUD STUDY 

What kinds of clouds are visible ? If more than one 
kind, what is the predominant kind? What percentage 
of the sky is covered ? (Estimate in tenths.) What is 
the prevailing direction of cloud movement? How 
does this compare with the direction of the surface 
winds ? 



48 MANUAL OF PHYSICAL GEOGRAPHY 

Tabulate these facts from observations made daily 
every two hours. Compare the clouds in morning, mid- 
day, and evening. If possible, get observations in 
winter and summer. 

From your observations, note the predominant kinds 
of clouds and the percentage : (a) in front and rear of 
a cyclone, (b) in an anticyclone. 

*42. OBSERVATION OF FROST CONDITIONS 

Note the following conditions when frost has occurred : 
Is the frost light or heavy ? What was the tempera- 
ture before the frost ? After the frost ? If maximum 
and minimum thermometer readings are available, note 
them. Was the sky cloudy or clear? Was the air 
quiet or moving ? What was the relative humidity be- 
fore the frost ? Was the locality subject to frost on a 
hill, in a valley, or both ? What was the surface of 
the ground — stony, loam, clay, pavement, etc. ? Is 
there any difference in the amount of frost on different 
objects ? Did the frost occur in a cyclone or an 
anticyclone and in what part, east, west, north, or 
south, or was it local ? 

Write a concise report on these frost conditions. 

Frost Forecast. — On several nights when you think 
that frost is likely to occur, observe and record the con- 
ditions named above. If frost does not occur, try to ex- 
plain the factors affecting its non-occurrence. 



MISCELLANEOUS CLIMATIC PHENOMENA 



49 



43. MAP STUDY OF FROST CONDITIONS 





Pressure 


Temper- 
ature 


Wind 
Direction 


Wind 
Velocity 


Sky 


Asheville, N.C. 


30.3 




S.E. 


6 


Clear 


Elkins, W.Va. 


30.3 


50 


N.W. 


4 


Clear 


Albany, N.Y. 


30.2 


40 


N.W. 


14 


Clear 


New York, N.Y. 


30.2 


50 


N.W. 


16 


Clear 


Detroit, Mich. 


30.2 




W. 


4 


Cloudy 


Nashville, Term. 


30.2 


60 


N.E. 


4 


Clear 


Charleston, S.C. 


30.2 


60 


E. 


14 


Clear 


Tampa, Fla. 


30.1 


70 


N.E. 


12 


Cloudy 


Mobile, Ala. 


30.1 


70 


N. 


8 


Cloudy 


St.Louis, Mo. 


30.1 


60 


S. 


12 


Cloudy 


White River, Ont. 


30.1 




w. 





Cloudy 


Montreal, Quebec 


30.1 




N.W. 


12 


Cloudy 


Northfield, Vt. 


30.1 




N. 


10 


Clear 


Corpus Christi, Tex. 


30 


70 


S.E. 


6 


Clear 


Oklahoma, Ok. 


30 




S. 


12 


Clear 


Kansas City, Mo. 


30 




S. 


10 


Clear 


Milwaukee, Wis. 


30 




s.w. 




Rain 


Duluth, Minn. 


30 


40 


N.E. 


12 


Rain 


Winnipeg, Man. 


30 




E. 


4 


Cloudy 


Havre, Mont. 


30 


50 


E. 


4 


Cloudy 


Del Rio, Tex. 


29.9 




E. 


8 


Rain 


Amarillo, Tex. 


29.9 


60 


S. 


18 


Clear 


Topeka, Kan. 


29.9 




S.E. 




Clear 


St. Paul, Minn. 


29.9 


50 


E. 


6 


Cloudy 


Miles City, Mont. 


29.9 




N.E. 


4 


Rain 


Tacoma,Wash. 


29.9 




S. 


4 


Clear 


El Paso, Tex. 


29.8 




E. 


4 


Cloudy 


Dodge, Kan. 


29.8 


60 


S.E. 


18 


Clear 


Sioux City, la. 


29.8 


60 


S. 


4 


Cloudy 


Yellowstone Park 


29.8 




N.W. 


4 


Cloudy 


Walla Walla, Wash. 


29.8 




E. 


4 


Clear 


Reno, Nev. 


29.8 




W. 


14 


Cloudy 


Yuma, Ariz. 


29.8 


60 


N.W. 


4 


Clear 


Flagstaff, Ariz. 


29.7 


60 


N.W. 


4 


Clear 


Pocatello, Id. 


29.7 




W. 


4 


Clear 


Boise, Id. 


29.7 




S.W. 


8 


Cloudy 



50 MANUAL OF PHYSICAL GEOGRAPHY 

Draw the isobars and isotherms. Where is there a 
cyclone ? Where an anticyclone ? Draw the wind ar- 
rows. Shade the areas where the sky is cloudy. 
Where and how many areas are there ? How are these 
areas related to the cyclone and anticyclone ? In gen- 
eral, which way do the isotherms bend, north or south ? 
In this case, is this due to wind direction ? If not, to 
what cause ? 

During the night previous to these readings, there 
was frost in western North Carolina and Virginia, 
West Virginia, Ohio, Pennsylvania, New York, and 
the interior of New England. Compare the frost area 
with the rest of the country as to the following 
factors, and state the effect of the factors on frost 
formation : state of sky, wind velocity, position in 
cyclone or anticyclone. Why should the interior, and 
not the coast of New England, be subject to frost? 
Other things being equal, which station would be more 
subject to frost, Havre, Mont., or Elkins, W.Va. ? Ex- 
plain what factors favored frost at Elkins and not at 
Havre. 

*44. LOCAL FORECASTING 

Note the weather maps for several preceding days. 
On the day preceding your forecast, was your locality in 
a cyclone, anticyclone, or was there neither ? If there 
was a cyclone or an anticyclone, was it strong or weak ? 
In what part of the cyclone or anticyclone was your 



MISCELLANEOUS CLIMATIC PHENOMENA 51 

locality ? What was its average progress per hour ? In 
what direction was it moving ? Were the barometric 
gradients strong or weak ? Were the winds gentle or 
strong ? Were the temperature changes around it slight 
or marked? What were the accompanying states of 
sky and precipitation ? 

From these data, forecast for your vicinity the tem- 
perature, wind direction and velocity, state of sky, and 
precipitation. If your forecast proves to be wrong, de- 
termine carefully the reasons why it is wrong. 

If recent maps are not available, older maps can be 
used. Make at least one forecast for your vicinity in 
summer and in winter. 

45. A STUDY OF OCEAN CHARTS: TRADE WINDS, ICE- 
BERGS, FOG, AND SAILING ROUTES 

A study of the pilot charts of the North Atlantic 
Ocean. Use the charts for January and July. If pos- 
sible, use charts for all the months. 

What department of the government issues these 
charts ? 

On a blank map, sketch the northern limits of the 
trade winds for January and for July. Through how 
great a distance do the trades here shift ? Why do they 
shift? On the average, how wide is the belt between the 
northeast trades and the southeast trades ? In general, is 
the region of tropical rains ivithin one of the trade-wind 



52 MANUAL OF PHYSICAL GEOGRAPHY 

belts or between them ? On your blank map, sketch its 
positions for January and July. 

What is the prevailing wind direction in the two 
trade-wind belts? What other winds blow? About 
what is the proportion of winds from other than the 
prevailing directions? (See the "explanation," at the 
bottom of the chart.) How do the wind directions in 
the northern trade-wind belt compare with the direc- 
tions north of this belt (the westerly drift belt) ? 

When in the year are icebergs most likely to be met ? 
What effect does this have on the steamship routes be- 
tween New York and London ? Sketch these routes 
for January and July on your blank map. 

Where are the regions of fog ? Where is the principal 
region ? When is fog most common, in winter or 
summer? About how large is the Newfoundland fog 
area in July ? How would you explain the difference 
in size of the fog areas in January and July ? 

Sailing Routes. — Sketch the sailing route from 
London to New York. How and why does it differ 
from the steamship route ? Sketch the sailing routes 
from New York to the equator and from the equator 
to New York. Contrast and explain them. Contrast 
and explain the sailing routes from England to the 
equator, and vice versa. 



MISCELLANEOUS CLIMATIC PHENOMENA 53 

*46. LOCAL, INDIVIDUAL, OR CLASS STUDIES 

(In all readings, it is well to have two or more persons make the readings 
so as to check results. ) 

Temperature. — Record the temperature at least twice 
a day during the school year. From the weather maps, 
determine the temperature gradient for each day. 

Pressure. — Record the pressure at least twice a day, 
and from the weather maps determine the barometric 
gradient for each day. 

Winds. — Record the direction at least three times a 
day. If there is access to an anemometer, get the wind 
velocities from that. If not, classify the winds as calm, 
gentle, strong, gale. 

State of Sky. — Estimate, in tenths, the amount of 
the sky covered by clouds. Kinds of clouds and their 
direction of motion, if moving. 

Relative Humidity. — Determine the relative humidity 
for each day, taking the readings at the same hour each 
day. 

At the end of each week, bring the data together. 
Correlate the temperatures and wind directions. What 
winds briny; warm weather ? Cool weather ? What re- 
lation between relative humidity and the temperature 
and wind direction ? What relation between the state 
of the sky and temperature ? Wind direction and pres- 
sure ? What relation between barometric gradients and 
wind velocity ? 



CHAPTER VI 

COMMON MINERALS AND ROCKS 

*47. COMMON MINERALS 

Most of the common minerals may be recognized by 
their physical characteristics. Color is usually some- 
what variable, but the streak, that is, the color of the 
powdered mineral, is characteristic. Simply rubbing the 
mineral on a file will give the streak unless the mineral 
is very hard, in which case it may be powdered. Hard- 
ness is important and for rough work may be graded as 
follows : minerals easily scratched by the thumb nail are 
very soft; those not easily scratched by the thumb nail 
are soft ; those that cannot be scratched by the thumb 
nail and are easily scratched by a knife blade are hard ; 
and those that cannot be scratched by a knife blade are 
very hard. Cleavage is very important, but not all min- 
erals show cleavage. Calcite has very good cleavage. 
The main things to note about cleavage are : In how 
many directions does it cleave (e g. mica cleaves in only 
one direction) ; at what angle do the cleavages run 
if there is more than one direction, and into what cleav- 
age forms do they divide the mineral {e.g. the cleavages 

54 



COMMON MINERALS AND ROCKS 55 

of calcite are in three directions, and meet at oblique 
angles giving a rhombohedral cleavage form) ? The 
cleavage can be ascertained by placing a dull knife blade 
against the mineral and lightly tapping the knife. Hold 
the knife blade at different angles and directions, to see 
if the mineral has any cleavages. If the mineral has 
a crystal form, this is very important to note. But the 
crystal form is to be distinguished from the cleavage 
form. If there is no cleavage, the fracture is sometimes 
distinctive. For instance, the shell-like or conchoidal 
fracture of quartz is an important characteristic. The 
weight, whether light, medium, or heavy, is important. 
If there is time and suitable apparatus, the specific grav- 
ity of the minerals may be found. Effervescence with 
weak hydrochloric acid is an indication of carbonates of 
which the principal common mineral is calcite. 

Describe the following minerals as to color, streak, 
hardness, cleavage, crystal form, fracture, weight, action 
with acid, and other characteristics : quartz, feldspar, 
calcite, fmorite, barite, pyrite, hematite, magnetite, limo- 
nite, galena, hornblende, mica. 

*48. ROCKS 

Sedimentary Rocks 

Shale. — Are its particles coarse or fine ? How many 
different minerals can you find ? Is it stratified? Lam- 
inated ? Hard or soft ? If ground up, would it make a 



56 MANUAL OF PHYSICAL GEOGRAPHY 

clay or mud ? What is its color ? To what does its 
color seem due ? What seems to be the cement ? 

Sandstone. — Are the sand grains coarse or fine ? 
What is the color of the sandstone as a whole ? Of the 
sand grains ? Is the cement calcite, an iron compound, 
or silica ? How can you tell if it is calcite ? (If an 
iron compound, it will usually stain the stone.) Are 
the sand grains angular or rounded ? If the latter, what 
is the probable cause of their smoothness ? Is the rock 
firm or friable ? Hard or soft ? Are there any traces of 
stratification in it ? Of what mineral is the sand princi- 
pally composed ? Is it a pure sandstone or does it have 
lime or clay ? Would it make a good building stone ? 
Why? 

Conglomerate. — What is the size of the largest pebble ? 
What is the average size ? What is the cement ? What 
is the shape of the pebbles ? Why ? Is the rock as a 
whole hard or soft ? Firm or not ? Is there any trace of 
stratification ? Are bedding planes more or less distinct 
in shales and sandstones than in conglomerates ? Why ? 

Limestone. — How does it behave with acid ? Why ? 
Is the calcite crystallized so you can readily detect its 
physical characteristics ? Powder some of the rock and 
dissolve it and note the residue, if any. (Usually a 
limestone contains a considerable amount of clay.) 
What is the color of the rock ? Is it massive, or has it 
bedding planes ? 



common minerals and bocks 51 

Igneous Rocks 

Granite. — Is its texture granitic or porphyritic (i.e. 
are all or only a part of its minerals distinctly crystal- 
lized ) ? What minerals can you determine ? What are 
the principal minerals ? What is the color of the rock ? 
What minerals give its color ? Would you describe the 
rock as a whole as hard or soft ? Firm or friable ? Do 
the minerals vary in size ? If so, which are larger ? 

Diorite. — What is its texture ? Color ? Can you de- 
termine any of the minerals ? Why is it harder to de- 
termine the minerals than in granite ? Is it heavier 
or lighter than granite ? 

Basalt. — What is its color ? Texture ? Weight ? 
Does it have as much quartz as granite ? Are the 
black and heavy minerals more or less prominent than 
in granite ? What minerals can you identify ? 

Obsidian. — How does its texture compare with that 
of granite and diorite ? What is its color ? What is 
the color of a powdered piece ? Is it hard or soft ? 
Compared with the other igneous rocks, is it light or 
heavy ? Why can you not determine its minerals ? 

Metamorphic Rocks 

Gneiss. — What is the color ? What minerals do you 
find ? Which of the igneous rocks does gneiss resemble 
so far as the minerals are concerned ? How does the 



58 MANUAL OF PHYSICAL GEOGRAPHY 

arrangement of minerals differ from that of the igneous 
rocks? What minerals predominate? Is the rock as a 
whole harder or softer than granite ? Will it ordinarily 
split more or less easily than granite ? Why ? 

Schist. — Compare its structure with that of gneiss and 
the igneous rocks. What minerals do you find ? How 
does the amount of quartz compare with that of granite ? 
Of basalt ? Is it harder or softer than gneiss ? Would 
it split more or less easily than the igneous rocks? 
Why ? What minerals predominate ? 

Quartzite. — What is its composition ? How does it 
differ in appearance from sandstone ? How does its 
hardness compare with other rocks? Does it split 
easily ? Why ? 

Slate. — Does it have planes along which cleavage is 
easy ? What other rocks show this ? Is the cleavage 
better or poorer than in the other rocks ? What is its 
hardness ? Of what do you think it is composed ? 
What uses has slate? To what properties are these 
uses due ? 

Other things being equal, which do you think would 
weather the faster, limestone or sandstone ? Sandstone 
or shale ? Sandstone or granite ? Granite or schist ? 
Building stone must stand a high pressure and should be 
massive, so as not to present opportunity for uneven 
weathering. So far as utility is concerned, which do 
you think would make the best building stone, granite 



COMMON MINERALS AND ROCKS 59 

or gneiss? Gneiss or schist? Massive or bedded sedi- 
mentaries ? Which rocks do you think would be better 
looking for building purposes ? 

*49. FIELD STUDY OF A ROCK OUTCROP 

How great a thickness of rock is exposed? How 
great an area ? What kind of rock is it, igneous, sedi- 
mentary, or metamorphic ? How many varieties can 
you find ? Do you find any joints ? Note and report 
all features which you can find. 



CHAPTER VII 

THE CONTOUR MAP 

*50. CONSTRUCTION OF A CONTOUR MAP 

Part I. — The region selected should have steep and 
gentle slopes in proximity. Materials needed : drawing 
pads, ruler, compass, protractor, and some kind of a level. 

Two things must be decided on before mapping: the 
scale and the contour interval. The scale indicates the 
distance on your map that will represent a given distance 
of your area. If the area is small, a scale of 20 feet 
to the inch is convenient. This is expressed by the 
fraction ^q. The contour interval will vary with the 
heights to be represented, but an interval of 5 feet is 
convenient, since that is about the average distance 
from the eye to the ground. It is well to measure a 
straight line on some level portion as a base line, AB, 
Figure 8. 

From this base line points can be determined in two 
ways. If the point is near and easily reached, as points 
C and E, their direction can be taken from A or B, the 
distance measured, and the points determined on a map 
by a protractor and ruler. For instance, if C is south, 

60 



THE CONTOUR MAP 



61 



west 20° and 15 feet distant from B, it is located by 
drawing on the map an indefinite line from B at the 
proper angle, and then laying off the distance according 
to the scale adopted. 

If there is a more distant point which is not con- 
veniently reached, its angles at A and B can be found 
by the protractor, and 

9 1 

these plotted on the d 

map until their sides 
meet and the point D is 
located. Various mem- 
bers of the class can get 1 
distances and directions 
from trees, etc. A and 
B and these other 
points can be plotted 
later if desirable. 

When several points have been located, e.g. trees, 
rocks, etc., the work of locating the contours can be 
begun. At the lowest place in your area, say, point 
X, let some one stand at X and level to different 
places on the area, while others mark these places, e.g. 
with pieces of paper (1, 1, 1). The leveling can be 
done with an instrument or by looking across the water 
in a tumbler. The points 1, 1, 1, all lie on a plane 
about 5 feet above X, and these points can be located as 
described above. Many of them can be put in with 




Fig. 8. 



62 MANUAL OF PHYSICAL GEOGRAPHY 

sufficient accuracy by sketching. When enough have 
been located, connect them, and you have your first con- 
tour line. A second can be made in like manner, by 
standing at one of the points 1 and repeating the 
process, locating points 2, 2, etc. 

STUDY OF A CONTOUR MAP 

Lock-port Quadrangle, Neiv York 
(It would be well to substitute the home quadrangle if it is mapped.) 

Part II. — What is the scale ? How many inches 
in the region does 1 inch on the map indicate ? How 
many miles ? What is the area of the quadrangle ? 
What is the contour interval ? What does the contour 
interval mean ? Where are the contours close together ? 
Where farthest apart ? What represent Streams ? 
Railroads ? Roads ? 

Starting south from Lockport, how far is it along the 
road to Millersport ? What do the figures 605, 601, and 
586 mean ? Where do you cross the 600-foot contour 
line? How far south do you have to go to reach it 
again ? Trace it as far as possible on the map. Where 
does it cross the Erie Canal ? If the sea should rise 600 
feet, what relation would it have to this contour ? In 
passing from Millersport to Lockport are you going up- 
hill or downhill ? How do you know from (1) the con- 
tours, (2) the streams ? At what height is the contour 
line north of Mud Creek near Millersport ? How far is 



THE CONTOUR MAP 63 

it from Mud Creek north along the Lockport-Millersport 
road to the 600-foot line ? To the 620-foot line ? To the 
640-foot line? Make a profile along the road from 
Millersport to the 640-foot line. (Starting at Millersport, 
measure to the 580-foot line. It is about one eighth of an 
inch. Draw a line this long on your cross-section paper. 
Measure the distance to the same contour line across the 




Fig. 9. 

creek. Let each vertical square on your paper represent 
20 feet. We cannot tell the depth of the creek between 
the contours, except that it is not 20 feet. Why ? From 
this line measure to the next 580-foot line at Mud Creek. 
Here, again, we do not know the depth of Mud Creek 
below this line, so we are at liberty to put it at any depth 
below one square as we think best. (See Figure 9.) 
From the contour north of Mud Creek to the 600-foot 
line is 2 inches and one square higher. From this point 
to the 640-foot line is 1^ inches and a square higher. 
The profile will be as shown in Figure 9.) 



64 MANUAL OF PHYSICAL GEOGRAPHY 

You will note that the vertical scale is different from 
the horizontal scale. Which is the larger ? What frac- 
tion expresses the horizontal scale ? What the vertical 
scale ? Why, on this profile, is it necessary to exagger- 
ate the vertical scale ? 

Would you call this region smooth or rough ? Its 
slopes steep or gentle ? How far is Raymond (northeast) 
from Millersport ? How high above the sea level is the 
hill northeast of Raymond? Are its northeast and 
southwest slopes equal ? At a point 2^- inches from the 
east side of the map and 5 inches from the north side 
make a profile to the north 5 miles long. How does it 
compare with the first profile ? What differences in 
level ? Is the slope gradual or irregular ? How high is 
the escarpment? What is the average slope per mile 
over the escarpment from the 600-foot line to the 500 
foot line ? When the contours are far apart, what does 
that show as to slopes ? When close together ? Which 
way does Tonawanda Creek flow ? How do you know ? 
(Note where the 600-foot line and where the 580-foot 
line cross it.) Where are its slopes steepest, in the 
upper or lower course ? Do contours point up or down 
a valley ? Why ? Do they point up or down a ridge ? 
Why ? Find slopes of principal valleys ; of the various 
escarpments. In any maps always determine contour 
interval and scale before reading them. 

Problems. — (It is not to be thought that the drawings 



THE CONTOUR MAP 65 

should be alike. They may look unlike and yet fulfill 
the conditions of the problems.) 

1. Draw a hill 2 miles long and 1 mile wide at the 
base and 100 feet above the surrounding country. (Use 
a 25-foot contour interval.) 

2. A hill of the same dimensions with — 

(a) steep slope on the north and gentle slope south. 
, (b) steep slope on the south and gentle slope north. 

3. Two level surfaces separated by an escarpment 200 
feet high (50-foot contour interval). 

4. Using a contour interval of 20 feet, draw a hill 
200 feet high above a plain, with a slope to the north 
of 200 feet to the mile and to the south of 400 feet 
to the mile. 

5. Using a contour interval of 25 feet, draw a valley 
with an average slope of 25 feet to the mile ; of 50 feet. 

6. Draw a valley in a level plain 75 feet deep near 
its head and 200 feet deep at its mouth. 

7. Using a contour interval of 20 feet, draw a valley 
with a slope of 40 feet to the mile, its head being 20 
feet below the surrounding country and its mouth 100 
feet. 



CHAPTER VIII 

WEATHERING, STREAMS AND STREAM VALLEYS 

*51. FIELD STUDY OF WEATHERING. A VISIT TO A 
QUARRY OR ROCK OUTCROP 

What kinds of rock ? Hard or soft ? Is it homoge- 
neous (of the same kind) or of different kinds ? Is it 
stratified or massive ? Are the fresh fractures smoother 
or rougher than the older fractures ? Why ? (The 
answer will depend upon the kind of rock.) Are sharp 
edges and corners more or less weathered than the flat 
surfaces ? Why ? Which exposes the most surface to 
weathering, the corners or the flat surfaces ? Are there 
joints in the rock? Are the joint planes weathered? 
Why ? If you can observe limestone, are there any 
cavities ? Is there any evidence of iron (stains) ? 
Observe all the instances you can of the work of the 
oxygen and carbon dioxide of the atmosphere. What is 
the depth of the soil ? What is its color ? To what is 
any dark color due ? Is it derived from the underlying 
rock ? How do you know ? What effect has the decay 
of vegetable matter on the ability of the ground water 
to accomplish weathering? Can you find examples? 

66 



WEATHERING, STREAMS AND STREAM VALLEYS 67 

Do you find any examples of weathering work by trees ? 
By animals ? By frost ? 

Break off a piece of rock. How do the fresh and the 
weathered surfaces compare ? How deep is the zone 
due to weathering visible? Is this part of the rock 
stronger or weaker than the fresh part ? Why ? 

Visit a rock exposure in winter. Do you find 
examples of the prying effect of ice ? Pick off a piece 
of ice from the rock surface. Is the contact side clean ? 
Why ? What bearing on ice work has this fact ? 

Soil. — Is it mostly of sand ? Or clay ? Or gravel ? 
Or a mixture of sand and clay (loam) ? In each case 
from what kind of rock could it have come? 



*52. FIELD STUDY OF STREAM WORK 

How wide is the stream ? How deep ? What is its 
slope in 100 yards ? What is its average slope per foot ? 
At this rate what would be its slope per mile ? (The 
slope can be determined by leveling along the water's edge 
in the same manner as shown in Exercise 50.) What is 
the velocity of the stream per mile ? (Note the time it 
takes a floating object to pass over a measured distance.) 
In the straighter courses of the stream where is the 
fastest current, at the sides or in the middle ? What is 
the velocity in the middle ? At the sides ? Note the 
same points in the meander of the stream. Make a 



68 MANUAL OF PHYSICAL GEOGRAPHY 

diagram of the straight course and of the meander, 
showing the " thread of the fastest current." 

The Stream Load. — Is the stream at present carrying 
a visible load? (If not, visit it during high water.) Of 
what does its load consist, mud, sand, or pebbles, or 
all of these? Where is the stream water clearest, in 
places of swift or slow current ? Why ? Is there any 
gravel ? If so, of what material ? Is it angular or 
round ? Do you think the gravel has been rounded by 
the stream ? (This should be answered with caution in 
a glaciated region.) What is the average weight of the 
pebbles that the stream moves? What is the weight of 
the largest rock that the stream has moved ? 

The stream's invisible load may be detected by allow- 
ing a drop of the water to evaporate on glass. What is 
the color of the residue ? Test it with acid. If there 
are laboratory facilities, evaporate a given quantity of 
water and determine the weight and composition of the 
invisible load. 

Stream Erosion and Deposition. — Is the stream at the 
place of observation eroding, depositing, or at grade ? 
What has it been doing in the past ? How do you know ? 
Are there flood plains ? If so, how wide ? Do they slope 
toward the stream or away from it ? Does the flood 
plain join the valley side by a gradual or a steep slope? 
Of what material is the flood plain composed ? Does 
the flood plain material differ in kind or in fineness as 



WEATHERING, STREAMS AND STREAM VALLEYS 69 



you go away from the stream? Does the flood plain 
slope downstream ? Does it slope at the same rate as 
the stream ? Are there bars in the stream ? Can you 
account for them ? What are they composed of ? Ex- 
amine the work of a stream in a meander. Where is 
it corrading ? Where depositing ? Contrast with stream 
work in a straight reach. Examine several meanders 
and note the stream action at 
points A, B, C, D, E, and F, 
Figure 10. Does a meander as 
a whole move up- or down- 
stream, or is it stationary? 
Why do you think so ? Do 
you find any meander that has 
moved downstream, thus open- 
ing up the valley (lateral plana- 
tion) ? If so, describe it. If you find a well-developed 
meander, describe as to length and steepness the slopes 
at GF, GE, and GD. 

The Stream Valley. — How wide at the bottom ? At 
the top ? How deep is the valley ? Do you think the 
valley is due to the work of the stream or not ? Why ? 
Does the valley follow all the curves of the stream ? 
Does it follow the main curves ? Is the valley narrow 
or wide at the bottom as compared with its top ? Is its 
section F-shaped or C7"-shaped ? 

Are the valley sides perpendicular, nearly perpendicu- 




Fig. 10. 



70 MANUAL OF PHYSICAL GEOGRAPHY 

lar, or sloping ? If sloping, is the slope uniform ? What 
is the average slope of the valley sides ? (Hold a clinom- 
eter so its base coincides with the sky line of the valley 
slope, and read the inclination. A common protractor 
can be used, or a serviceable clinometer can be made on 
the inside of your notebook cover, Figure 11. A button 




Fig. 11. 

or half of a bullet will make a good weight.) Is the 
slope at the bottom as steep as at the top ? Why ? Are 
there marked changes in the slope ? If so, are they due 
to a difference in rock ? Are the two valley slopes 
equally steep in the straight reaches ? In the meanders 
of the valley ? Are there cliffs ? If so, to what are 
they due : to differences in the rock or to stream work 
at the base ? If the former, make a sketch of the rock 
arrangement ; if the latter, explain in full. 

Is the top of the valley wider or narrower than the 
bottom ? How much ? Give all the reasons for this 



WEATHERING, STREAMS AND STREAM VALLEYS 71 

that you can. Which are most important ? In which 
part, the top or the bottom, is weathering the more im- 
portant ? Corrasion ? Which part has been longer 
exposed to weathering ? 

Stream Tributaries. — Does the tributary valley at its 
junction with the main valley point up or down the lat- 
ter valley ? At what angle ? (This can best be deter- 
mined from a good map if one is at hand.) Does the val- 
ley narrow or widen as you go up it ? Give all possible 
reasons for your answer. Do the slopes of the valley 
sides change as you go up ? How ? Why ? Make 
cross sections of the valley in its lower and upper por- 
tions. Select a short valley, level up the valley as de- 
scribed in Exercise 50, and, from your data, plot a 
longitudinal profile of the valley. Is the curve as a 
whole concave or convex to the sky ? Where is it steep- 
est ? Where least steep ? Why ? Are there any sud- 
den changes in the curve causing rapids or waterfalls? 
If so, explain the cause. 

Does the tributary stream enter the main stream at 
grade ? Can it erode below the level of the main stream 
(its local base level) ? Compare the corrasion and depo- 
sition of the stream in its upper and lower portions. 

Does the stream reach the ground water level at any 
place (shown by springs) ? Is there a different ground 
water level for wet and dry times? Is the stream inter- 
mittent in any portions of its course ? Why ? 



72 



MANUAL OF PHYSICAL GEOGRAPHY 



Interstream Areas. — What is the width of the area 
between streams ? Does it slope gently or sharply to 
the streams on either side ? Describe the dissection of 
its surface. Does the amount of dissection change in 
passing away from the main stream ? 

Is the divide distinct or indistinct ? Broad or narrow ? 
Flat or with marked slopes ? Does its distinctness change 
in going towards or away from the main stream ? Is 
the divide midway between the two streams on either 
side? Toward which stream is the divide likely to 
migrate ? Why ? 



Fig. 12. 



53. WEATHERING AND CORRASION CURVES 

Weathering Curve. — Assume the block ABCD, Fig- 
ure 12, to be of uniform composition and exposed to 
uniform weathering on all sides. In 
this process the block will be reduced 
in size. Will it retain its rectangular 
shape ? What did you determine as to 
this in your field study of rocks with 
sharp angles and monuments with square corners ? 
Why do corners tend to become 
rounded ? Will the curves of the 
block ABCD be convex or concave 
to the sky? Such curves are called 
weathering curves. 

Corrasion Curve. — Assume block ABCD, Figure 13, 



Fig. 13. 



WEATHERING, STREAMS AND STREAM VALLEYS 73 

homogeneous as in Figure 12 and having a slope AB 
with a rainfall equal on all portions of the slope AB. 
In which way would the water run, toward A or B ? 
Would the volume of water be the same at A and B ? 
What effect would this fact have on the comparison of 
the erosion at A and B ? What part of the line AB 
would be eroded most rapidly? What kind of a curve 
would the line AB be at first ? After considerable 
period of erosion ? Would it be concave or convex to 
the sky ? What effect would such a curve have on the 
velocity of the water at B ? What effect would this 
in turn have on the erosion in the vicinity of B ? Such 
a curve is called a corrasion curve. Is this corrasion 
curve steeper in the vicinity of B than in the vicinity 
of At Why ? 

These type curves require a homogeneous material. 
If your region is composed of materials of different de- 
grees of resistance, the curves will be complicated, but 
can usually be recognized. 

Note the hills and valleys along the route of your 
field trip. Where, near the top or near the bottom of 
the hills, are weathering curves prominent ? Corrasion 
curves ? Note either of these curves on the valley sides. 
Sketch in contours examples of both curves. Which 
curve, the weathering or the corrasion curve, does your 
stream profile of Exercise 52 most resemble? How 
would you explain your answer ? 



74 MANUAL OF PHYSICAL GEOGRAPHY 

*54. STREAMS AND STREAM VALLEYS. GENERAL MAP 
STUDY OF STREAMS AND THEIR VALLEYS 

If the home area is mapped, note the following points 
on the local map : — 

What is the main stream valley ? How deep is it ? 
How wide ? Is its depth uniform ? If not, where is it 
deepest, in its upper or in its lower portion ? Is it 
uniformly wide ? If not, where is it widest, in the upper 
or in the lower portion ? Which portion of the stream, 
the upper or the lower, has the greatest volume of 
water ? Why ? What evidence of this in the width of 
the stream ? In the width of the valley ? Which por- 
tion of the stream valley is the oldest ? 

(Beginning at the lowest contour in the valley, rep- 
resent its position by point 1. Measure the distance 
up the valley side to the next contour line, transfer 
the distance to your coordinate paper and you have, 
say, point 2. In like manner get points 3, 4, and 5, as 
in Exercise 50, Part II. Connecting these points, you 
have a profile of one side of the valley. When the 
other side is completed, the two profiles give the valley 
cross section.) Which part of the valley has longest 
been subjected to weathering ? What relation has this 
fact to the width of the valley in various parts ? 

Make a cross section of the valley in its lower and in 
its upper part. (Use cross-section paper, allowing each 
small square to represent one or more contour intervals. 



WEATHERING, STREAMS AND STREAM VALLEYS 15 

If the relief is great a small square may represent sev- 
eral contour intervals so as to avoid too much exaggera- 
tion of altitude. The horizontal scale of your section 
is true, but your vertical section is exaggerated. How 
much is it exaggerated ? In such work the exaggera- 
tion should be the least possible and yet bring out the 
essential details. The student must develop his judg- 
ment as to the exaggeration of the vertical scale.) In 
which portion of the valley, the upper or the lower, are 
the slopes the steepest ? Account fully for this. 

How long is the valley ? How far is it in a straight 
line from its mouth to its head ? What is the altitude 
at or near its head ? At or near its mouth ? What is 
the average slope per mile ? Is the slope uniform ? 
If not, where is it steepest ? Make a longitudinal pro- 
file of the valley. (Unless the relief is great, allow one 
small square to represent the contour interval. If the 
valley is too long for your cross-section paper, the hori- 
zontal scale will have to be diminished in transferrins; 
to your profile. A convenient way is to transfer to the 
profile only half the distance on the map. Construct 
in the same way as in the valley cross section of this 
exercise.) Is your curve concave or convex to the sky ? 
Where is it steepest ? Why ? Does the steepness in- 
crease uniformly from the mouth to the head ? What 
are the reasons ? What is the slope per mile in the 
steep portion ? In the more level portion ? 



76 MANUAL OF PHYSICAL GEOGRAPHY 

About how many square miles are included in the 
drainage basin of the stream ? Are there any tributa- 
ries ? How many ? What is their average length ? 
Are the tributaries of the tributaries well developed? 
In general, do the tributary valleys point up or down 
the main valleys ? Do they all join the master streams 
at grade ? Does the stream follow a straight or a wind- 
ing course ? Does it meander in any portion ? If so, 
what, the upper or lower ? Do the curves of the stream 
always correspond to curves of the valley ? If not, 
where is there the least fitting of stream and valley 
curves, in the upper or the lower portions? In the 
steep or the more level portions ? 

If there is no local map available, the following quad- 
rangles will afford good examples : New Martinsville, 
Ohio; Highwood, 111. ; Pittsburg, Pa.; Marshall, Ark.; 
Guy an dot, W. Va.-Ohio. 

55. EEVERSED TRIBUTARIES 

New Martinsville Quadrangle, West Virginia-Ohio 

How far and in what direction from Cincinnati ? 
Pittsburg ? At what angle do most of the tributaries 
to the Ohio point ? Do they point upstream or down- 
stream ? Which way do the tributaries of the tributa- 
ries point ? Make a sketch map showing the Ohio and 
its main tributaries, and one showing Fishing Creek 
and its tributaries. How do they compare? The 



WEATHERING, STREAMS AND STREAM VALLEYS 77 

Ohio in this region is thought to have at one time 
flowed northward. What evidence of this former di- 
rection of flow is shown in this region? 

*56. A BRAIDED (ANASTOMOSING) STREAM 

Lexington Quadrangle, Nebraska 

In what part of the state is this region ? What part 
of the Platte River is here shown (upper, middle, or 
lower) ? Is the Platte River, as a whole, aggrading or 
degrading ? Why do you think so ? How wide is the 
belt subject to overflow at high water? How wide is 
the trench in which the river flows ? How deep ? How 
far below the bottom of this trench is the river ? Does 
the water usually run in one or many channels ? Do 
you think that the map was made when the river was 
in flood ? What is the average slope per mile on the 
stream ? Is this high or low as compared with most 
rivers ? Do you think, therefore, that the aggradation 
is caused by a change in slope or a change in volume ? 
Is the rainfall here heavy or light ? What bearing 
does this fact have on the preceding question ? Was 
the river following its present habit when it cut 
the deep, wide trench in which it flows ? Give a 
verbal picture of the river as you would see it look- 
ing up from the Lexington bridge. How is it similar 
to the streams with which you are familiar? How is 
it different? 



78 MANUAL OF PHYSICAL GEOGRAPHY 

Ishawooa Quadrangle, Wyoming 

Trace the Shoshone River. Where is it degrading ? 
Where aggrading ? What is its slope in feet per mile 
where it is degrading ? What, where it is aggrading ? 
Make a profile of the river marking the stretches where 
it is aggrading and where it is degrading. 

*57. FLOOD PLAINS. AN AGGRADING RIVER. NATURAL 

LEVEES 

Donaldsonvdle, La., Quadrangle 

How far and in what direction from New Orleans is 
Donaldsonville ? In general, how wide is the river 
here? Why can you not tell the width of the flood 
plain from this map ? Where, with respect to the river, 
is the highest land ? Where, the lowest ? Why is the 
country highest near the river ? How wide is the 
natural levee here ? Make a profile across the river 
and levees at Lilly. Are the slopes steepest towards or 
away from the river ? Explain fully the reasons. What 
is the slope in feet per mile from the top of the natural 
levee toward the river ? From the river ? How high 
is the back swamp above sea level ? 

Do all the tributaries run directly into the Mississippi ? 
Do most of them ? Why ? Is New River an aggrad- 
ing or degrading stream ? Is its natural levee higher 
or lower than that of the Mississippi ? Where do most 
of the people live ? What is the direction of a majority 



WEATHERING, STREAMS AND STREAM VALLEYS 79 

of the roads ? Do the numerous canals drain toward 
or from the river ? Why ? In 1890 the levee near 
Nita Crevasse broke. What connection between this 
and the irregular hills to the northeast ? Are these 
hills round or elongated ? Why? How high are they? 
The Indian mounds are thought to have been built for 
refuge in flood time. How high are they ? Where is 
the river most likely to break through the levee, at Nita 
Crevasse or Brilliant Point ? At Burnside or Cofield ? 
Why? 

Marysville, CdL, Quadrangle (Edition of January, 1895) 

How far and in what direction is Marysville from 
San Francisco ? Where does the Sacramento rise ? 
Into what does it flow, and where ? What height must 
an elevation in this map have to be shown by contours ? 
Why is so large a contour interval used ? What features 
has the Sacramento in common with the Mississippi at 
Donaldsonville ? How wide is the flood plain ? The 
natural levee ? The back swamps ? 

*58. A GRADED RIVER 
Elk Point Quadrangle, S.D., Neb., la. 

The Missouri River in this region is practically at 
grade. Is it markedly deepening its channel ? Is 
vertical or lateral corrasion most prominent ? How 
does it compare in this respect with the Ohio River in 
the New Martinsville region ? How does it compare 



80 MANUAL OF PHYSICAL GEOGRAPHY 

with the Platte? How wide is the flood plain in 
general? How far below' the uplands? About how 
far is the river surface below its flood plain? What 
is the river's slope between Vermilion and Ponca ? 
Would all streams meander with such a slope ? What, 
therefore, do you infer about the load of the Missouri ? 
Is the river now widening its valley at any place ? 
Where ? How ? How far is it from Vermilion Ferry in 
a straight line to where the river leaves the quadran- 
gle ? How far is it, measuring along the river ? What 
is the origin of Lake McCook ? Is its curve of larger 
or smaller radius than those of the river ? Why 
should they be so ? What does the slough southwest 
of Burbank indicate as to the former course of the 
river ? What is the probable origin of the slough near 
Elk Point ? Why does the Big Sioux turn and flow 
parallel with the Missouri? What recent cut-offs in 
the Big Sioux ? Has the Big Sioux a higher or lower 
slope than the Missouri ? Is the Missouri corrading 
its valley sides ? (This process has been termed lateral 
planation.) 

59. MISSISSIPPI DELTA 

East and West Delta, La., Quadrangles. Coast Chart, No. 194. Scale 

80000 

What are the scales of these maps ? Why is there 
no contour interval for the relief maps ? About how 
many square miles are included in the delta country 



WEATHERING, STREAMS AND STREAM VALLEYS 81 

from Head of Passes Light ? How much land above 
sea level ? Through how many main distributaries does 
the river discharge ? Does it discharge through other 
distributaries above these ? Make a sketch map show- 
ing the arrangement of distributaries. What is the 
width of each of the three distributaries ? About what 
is their depth? Where are they deepest, in their upper 
or lower courses ? Why ? Where would a ship have 
greatest difficulty in entering ? How is the ship channel 
improved in the South Pass ? Why are jetties built at 
the mouth of the pass ? What is the depth of water in 
them ? What is the depth of water in the mouths of 
the other passes ? How long are the jetties ? Why is 
a dam placed at the head of Grand Pass ? 

Taking the delta as a whole sooth of the junction of 
the passes, is it triangular ? Is the same outline to be 
seen at the mouths of any of the distributaries? Is 
the land at the forks triangular ? What explanation ? 
Taking the delta as a whole, does it slope uniformly 
beneath the water ? (For answer make a profile from 
the head of the passes on Garden Island Bay or East 
Bay to the 10-fathom line.) Allow each small square 
to represent 1 fathom. Note the values of the figures 
within the dotted surface. Where are the most gentle 
slopes ? At what depth is the steepest slope ? What 
is its slope per mile? Take a subordinate delta, such 
as that at the mouth of Pass a Loutre, or that at the 



82 MANUAL OF PHYSICAL GEOGRAPHY 

junction of Northeast Pass and Southeast Pass (south- 
west of Blind Bay), or that at the mouth of Southwest 
Pass, and make a profile. How do the slopes compare 
with those of the delta as a whole ? How many marked 
slopes in all of them do you find ? How much change 
in sea level would leave most of the delta dry ? How 
much would submerge all ? Are there lakes included in 
the delta ? What ? 

60. ALLUVIAL FANS 
Cucamonga, Cal., Quadrangle 

* Part I. — How far, and in what direction from San 
Francisco ? From Los Angeles ? What divisions of 
this region could be made on the basis of altitude ? 
What is the general height of the highlands ? What is 
the difference in altitude of highlands and lowlands ? 
In how many miles does their change of altitude occur? 
What, therefore, is the slope per mile between them ? 

Make a profile along San Antonio Valley from the 
4500-foot contour to the 750-foot contour. What is 
the average descent per mile of the profile ? What is 
the descent in the canon ? Below the canon ? What 
effect would this change in slope have on the velocity 
of the stream ? Upon the carrying power ? Where is 
the stream evidently degrading ? Where aggrading ? 
How far below the mouth of the canon do the contours 
bow out f How long is the alluvial fan built by the 



WEATHERING, STREAMS AND STREAM VALLEYS 83 

stream ? How wide at its widest part ? What is its 
approximate area in square miles ? (The area of a tri- 
angle is one half the product of its base by its altitude.) 
What is its approximate area in acres (640 acres in 
1 square mile) ? Where does the stream disappear in 
the fan ? Where does it reappear ? Does it reappear as 
a single stream ? How far between the disappearance 
and the reappearance? Where would you infer that 
the stream would drop its heaviest and coarsest load, at 
the apex or the margin of the fan ? Why ? Why, 
therefore, does the stream disappear at the apex of the 
fan ? What is the slope of the fan ? The horizontal 
outline ? The general shape ? How do these compare 
with similar features of the Mississippi delta ? 

Are there other fans ? How many ? Which is the 
largest ? Which has steepest slopes ? Which is the 
smallest? Which stream has the largest drainage 
basin ? Which, the smallest ? Is there any relation 
between the size of the drainage basin and the size of 
the fans ? Are the fans distinct from each other ? 
At about what contours do they seem to coalesce? 
Such coalesced fans are sometimes called inidmont 
or compound fans. Which are the most dissected, the 
fans or the mountains ? Which are the youngest in 
actual age ? Which in stage of erosion ? What in- 
ference as to the rainfall of the region can you make 
from : the intermittent streams ; the number of streams ; 



84 MANUAL OF PHYSICAL GEOGRAPHY 

the dissection of the fans ? • What can you say of the 
water-power facilities in the mountains ? Upon what 
part of the fans are most of the towns? Sketch a 
typical fan. 

BRAIDED RIVER AND ALLUVIAL CONES 

Corona Quadrangle, California 

Part II. — What is the fall per mile of the Santa 
Anna River from the northeastern part of this area to 
the town of Yorba? From Yorba to near Garden 
Grove? From near Garden Grove to the sea? Where 
has this river built an alluvial fan? How wide is the 
fan ? What is its slope per mile ? Do all of the flood 
waters of the river pass through its present channel ? 
What channel to the north is sometimes used ? Where 
does the river fill its channel ? Where does it become 
" braided " ? How does its slope explain its braiding ? 
How does the material through which it flows ? Where 
does Santiago Creek become braided ? How does its 
slope in the braided reach compare with that in 
the upper course ? How would you account for this ? 
Describe the gentle slopes south of Corona with their 
drainage. Are most rivers braided in their lower 
course, as the Santa Anna ? Why ? In what part 
of its course is the Platte braided ? From the size 
and number of streams and the number of tributaries, 
can you infer the rainfall of the region ? 



WEATHERING, STREAMS AND STREAM VALLEYS 85 

In what physiographic regions is population dense? 
What means of irrigation do you find ? Trace the 
Orange and Santa Anna Canal. 

61. RIVER DEPOSITS. BARS 

Almost any chart of the Mississippi River will show 
bars. The charts below Cairo are especially good. The 
following charts are useful : numbers 7, 8, 10, 16, or 
20 (charts of the Lower Mississippi, scale 2~oo~oo)- 
How many bars do you find ? What is their average 
length ? Width ? Are they rounded or elongate ? Do 
they occur for the most part at the sides or in the middle 
of the river ? Why ? On a meander, do they generally 
occur on the inside or the outside of the meander ? 
Why ? Is a bar often formed where a tributary enters ? 
Why ? Do they occur on the upstream or the down- 
stream side of the tributary ? Why ? How high, in 
general, are the bars above the water ? Find and sketch 
a type bar in a straight reach ; in a meander ; at the 
entrance of a tributary. 



62. FLOOD PLAIN MEANDERS 



#1 



Tart I. — The following charts of the Mississippi 
River show meanders and their accompanying phe- 
nomena : numbers 13, 14, 20, 18, 8, scale 2o"oo~o- 

How is the depth of the river shown ? The eleva- 
tion of the land ? Make a profile of the river bottom 



86 MANUAL OF PHYSICAL GEOGRAPHY 

across the river, at the beginning, middle, and end of the 
meander. Where is it deepest at these points ? Where 
is it cutting most ? Where, with respect to a " tongue " 
(the land extending into a meander), is the river 
depositing in most cases (upstream or downstream 
from the " tongue ") ? Are there any cut-offs ? If so, 
are they filled at either end ? Does the resulting oxbow 
lake show the same shaped bottom as the meanders in 
the present stream ? What is the length of the oxbow 
lake ? How much did the river shorten its course 
when the oxbow lake was formed ? How does the 
curvature of the oxbow lakes compare with that of 
the meanders ? Are there any impending cut-offs ? 
How much has the river yet to do to cut through the 
base or " neck " of " tongues " ? 

Bayou Sara Quadrangle, Louisiana 

Part II. — How far is this region from the mouth of 
the Mississippi ? About how high is the river above 
sea level ? About how wide is the river ? Trace the 
levee. Why is there no levee on the east side of 
the river ? About how wide is the valley between the 
levee and the upland on the east ? What is the general 
altitude of the upland ? 

How long is False River ? What physiographic 
term would apply to it ? How wide is the old " tongue" 
through which the Mississippi has cut? How much 



WEATHERING, STREAMS AND STREAM VALLEYS 87 

did the river shorten its course ? Do you infer that the 
cut-off is recent ? Why ? What fraction of False River 
has been filled ? How high is the filled portion above 
the present False River ? How does the altitude of 
this part compare with that of the surrounding country ? 
Has False River any outlet ? Which way does Grand 
Lake drain ? Note the streams flowing northward in 
the region south of False River. How do many of them 
end ? Why ? How does the curvature of False River 
compare with that of the present meanders ? Does 
Bayou Sara empty directly into the river ? How 
high is the cliff west of Springfield Bend ? How far 
can you trace it ? What made it ? Take any chart 
(scale 6 3^60") of the Mississippi River. Note the 
meaning of the red lines and the black lines. Where 
has the river built its banks ? Where has it cut its banks? 
Does this occur for the most part in the straight or the 
curved portions of the river ? Which process, for the 
most part, occurs on the upstream side of spurs ? 
Which on the downstream side of spurs ? Sketch good 
examples. What landings have changed their position, 
and why ? 

63. RIVER TERRACES 

*Part I. Hartford Quadrangle, Connecticut. — The 
river terraces of this region are best shown between East 
Windsor and Burnham. How wide is the first terrace ? 
How high above the river ? How high is the terrace 



88 MANUAL OF PHYSICAL GEOGRAPHY 

front ? What is the direction' and amount it slopes per 
mile ? How high above the first terrace is the second 
terrace ? How wide is it ? How far along the river 
can you trace the first terrace ? How high is it above 
the river at East Hartford ? At South Windsor ? At 
East Windsor ? At the Warehouse Point ? Can you 
trace it on the west side of the river? Which way 
does the terrace slope ? Why ? Was the river aggrad- 
ing, or degrading, when the terrace was built? Which 
is the river doing now ? 

Part II. Peoria Quadrangle, Illinois. — The city of 
Peoria is built on a terrace. How high above the 
flood plain ? How broad ? Does it slope toward the 
river ? Away from the river ? How could you explain 
the depression in the northwestern part of the 
city ? How would you explain the bluffs back of the 
city ? How high are the bluffs ? Is there a correspond- 
ing terrace down the river ? Compare it in all respects 
with the one in which Peoria is situated. 

Sketch the best type of a terrace you can find. 
Note the levees in different places. 

64. STREAM CAPTURE 

*Part I. Kaaterskill Quadrangle, Neiv York. — How 
far, and in what direction, from New York City ? Note 
the escarpment of sandstone and similar rocks running 
across the map. How high is it? How steep is it? 



WEATHERING, STREAMS AND STREAM VALLEYS 89 

Is it dissected ? How many streams run across the 
escarpment ? Do they extend far back of the escarp- 
ment ? Trace the divide between the easterly and 
westerly flowing streams. How far is it from the es- 
carpment ? Which streams, the easterly or westerly 
flowing, have the greatest fall per mile ? Which way 
would you expect the divide to migrate ? Why ? At 
what kind of an angle do the tributaries enter Schoharie 
Creek ? Plattekill Creek ? What is the usual normal 
angle ? Taking the valley of the Plattekill, west of 
West Saugerties, compare its cross section in the 
Clove and above the Clove. Where is the valley 
widest ? Deepest ? Where are the sides steepest ? 
Do the lower and upper parts of valleys usually have 
these characteristics, or are they usually reversed ? If 
the Plattekill were to capture portions of the Schoharie, 
would the present arrangement of valley tributaries in 
the upper Plattekill, be explained ? Judging from the 
angle of its tributaries, where did the Plattekill begin to 
capture the Schoharie? Assuming this process of 
capture to continue, sketch the probable stream pattern 
of the Plattekill when it shall have captured the upper 
Schoharie at about one mile southwest of the Plaat Clove 
P.O. Has the same process been in operation on the 
Kaaterskill Creek ? Into what were South Lake and 
North Lake probably tributary ? Judging by the tribu- 
taries, where did the process of capture begin ? Can 



90 MANUAL OF PHYSICAL GEOGRAPHY 

you find any impending captures ? Sketch the present 
drainage of Kaaterskill, Schoharie, and Plattekill creeks 
in continuous lines, and the probable past extension of 
Schoharie Creek in dotted lines. 

The sharp turn in Plattekill Creek, southeast of Plaat 
Clove P.O., has been called an " elbow of capture." 
Find others. How do these elbows of capture show the 
fact that the divide between the east- and west-flowing 
streams has migrated, and the direction of its migration? 
Illustrate your answer. 

Reference. — Tarr's "Physical Geography of New York 
State," pp. 190, 191. 

Part II. Buckhannon Quadrangle, West Virginia. — 
In what part of the state is this quadrangle located? 
Into what does the Buckhannon River empty? 

West of the town of Buckhannon, locate and trace 
Brush Fork, Spruce Fork, Glady Fork, Right Fork of 
Stone Coal Creek, Pigeon Roost Fork, West Fork (Mo- 
nongahela River). 

Make a sketch map of all except the last. The Right 
Fork of Stone Coal Creek is tributary to the West Fork 
of the Monongahela River. How do the tributaries of 
the Right Fork indicate the direction of flow ? How do 
Spruce Creek and Glady Fork agree in this respect with 
the rest of the tributaries ? 

Does Brush Creek valley notably widen or narrow 



WEATHERING, STREAMS AND STREAM VALLEYS 91 

from the mouth upstream ? Is this the usual behav- 
ior ? How high is the divide at the head of Brush 
Creek ? Trace the divide between the West Fork (Mo- 
nongahela River) and the Buckhannon. Is it midway 
between the streams ? Which stream would you infer 
is most actively eroding ? The Buckhannon in this 
region is nearly graded, while the West Fork is in a 
younger stage of activity. Taking into consideration 
the activities of West Fork and of Buckhannon rivers, 
the tributary directions, the valley of Brush Creek, 
and the divide at the head of Brush Creek, work out the 
history of Brush Creek. Illustrate with maps, showing 
present and former conditions. There are other exam- 
ples in this region. What is the probable fate of the 
upper Buckhannon ? 

Beference. — Buckhannon Folio, West Virginia, U.S.G.S. 

65. YOUTHFUL TOPOGRAPHY AND DRAINAGE 

*Paet I. Fargo Quadrangle, North Dakota-Minn- 
esota. — In what part of the state is this region ? 
How far, and in what direction, is it from Milwaukee ? 
What is the general character of the topography ? What 
is the contour interval ? Draw a profile along the par- 
allel of 46° 50'. What kind of divides, flat or sharp? 
How would you describe the valleys as to depth, width, 
and steepness of valley sides ? Is the drainage well or- 
ganized ; i.e. is the country well drained ? Are there 



92 MANUAL OF PHYSICAL GEOGRAPHY 

many tributaries ? What is the length of the Red River, 
not taking into account the meanders ? What is its 
length including the meanders ? (To measure this, take 
a piece of fuse wire or a stiff string and lay it along the 
river. Then measure. Let one student measure in the 
first four squares, another in the second, etc. Then 
the sum of the measurements will be the length of the 
river.) 

What is the fall or slope of the Red River ? If you 
cannot get the exact figures, how close can you deter- 
mine it ? Does the country slope in the same directions 
as the rivers flow ? What relation does the meandering 
of the river have to these questions ? This region is a 
part of the bed of Lake Agassiz which once covered the 
Red River Valley. Why can the roads run so straight ? 
Do you think that the region has long been subject to 
erosion ? Why ? 

References. — Fargo Folio, TJ.S.G.S. ; The general region is 
described in Monograph 25, TJ.S.G.S. ; "The Glacial Lake 
Agassiz," by Warren TJpham. 

*Part II. Eagle Quadrangle, Wisconsin. — In what 
part of the state ? Is the run-off good ? Do the streams 
have steep or gentle slopes ? Do you think they are 
rapid or sluggish ? Are the tributaries well developed ? 
Are the divides distinct or indistinct ? Is the region 
dissected ? What proportion of the country is swampy? 
What proportion is covered with lakes? Do all the 



WEATHERING, STREAMS AND STREAM VALLEYS 93 

lakes have an outlet ? Are there any undrained de- 
pressions ? What stage of erosion does the country 
belong to ? Will the lakes probably become larger or 
smaller ? How ? Will the swamps increase or decrease 
in area ? How ? Will the divides become more or less 
distinct ? How ? During the glacial period the con- 
tinental glacier obliterated the preglacial topography 
and left the present surface. 

Eeference. — Professional Paper No. 34, U.S.G-.S., by William 
C. Alden. Plates and illustrations. 

Part III. Highwood Quadrangle, Illinois. — How far, 
and in what direction, is this region from Chicago ? Com- 
pare the divides with those in the Fargo and Eagle quad- 
rangles. Compare also the organization of the streams. 
Compare the run-off. Compare the streams in the belt 
east of the Chicago and Northwestern Railroad with 
those of the rest of the quadrangle. Compare the stream 
valleys. Which streams and valleys are the older in 
years ? Which are older in development or stage of 
erosion ? 

All of these quadrangles illustrate regions in the 
youthful stage of erosion. Enumerate carefully their 
characteristics of this stage. Some are farther advanced 
toward maturity than others. Note and describe these 
various stages of youthful topography and drainage. 

Supplementary. — Into what does the Desplaines 
River flow ? What is its slope per mile ? What is the 



94 MANUAL OF PHYSICAL GEOGRAPHY 

slope per mile of the streams flowing into Lake Michi- 
gan ? Which set of streams best show headwater ero- 
sion ? Why ? 

Eeference. — Professional Paper No. 34, U.S.G.S., by Wil- 
liam C. Alden, Plate III. 

Part IV. Youthful Topography and Drainage in 
Soluble Rock (mostly limestone). Arredono Quadrangle, 
Florida. — In what part of the state is this region ? 
What is the contour interval? What is the general 
altitude? How would you describe the surface — as 
level, rolling, or rough ? How does it compare with 
the Fargo, N.D., region ? Is the drainage well organ- 
ized ? Compare with the Eagle, Wis., region. Have 
all of the lakes outlets ? Inlets ? In a region of 
soluble rocks the streams often disappear and flow 
underground. Note the " sink " into which Hogtown 
Creek flows. Find other examples. These subterra- 
nean streams often reappear. Find an illustration on 
Hatchett Creek. (See Blue Spring and Wekiwa River. 
Dunnelon Quadrangle, Florida.) Could the absence of 
outlets of many of the lakes be accounted for by the 
rainfall of the region ? How ? What is the rainfall of 
Florida ? Does this reason hold for these lakes? Find 
sink holes. What is their origin ? 

Compare the stage of erosion of this region with the 
other regions taken up in this exercise. Which of the 
four regions are advanced in youth ? Which are less 



WEATHERING, STREAMS AND STREAM VALLEYS 95 

advanced ? From the drainage, how would you infer 
the solubility of the rocks ? 

*Part Y. Youthful River, Niagara Falls Quadrangle, 
New York. — How far below the general level of the 
country is the Niagara River above the falls ? Below 
the falls ? How would you classify each part of the 
river as to stage (youth, maturity, or age) in the cycle 
of erosion? Of what stage are the falls a characteristic ? 

66. MATURE RIVERS AND VALLEYS 

*Part I. Pittsburg Quadrangle, Pennsylvania. — 
How do the rivers shown here differ from youthful and 
old rivers in the kind of work they are evidently do- 
ing ? Is the Monongahela degrading or aggrading or at 
grade ? How wide a valley has it cut ? Is it cutting 
at all places ? Is it building at all places ? Where is it 
cutting ? Where building ? Are the main rivers cor- 
rading vertically ? Laterally (lateral planation) ? In 
general, do the streams show lateral corrasion in the 
straight reaches or the bends? Find and sketch a 
good example. (Sketch with contour lines.) Is the 
lateral corrasion greatest on the outside or the inside 
of a bend ? Why ? Are flood plains forming ? About 
what is their average width ? Are they forming in 
the straight reaches or the bends of the river ? On the 
outside or the inside of the bends ? On the down- 
stream or the upstream sides of the spurs ? Sketch a 
good example. 



96 MANUAL OF PHYSICAL GEOGRAPHY 

How wide are the river valleys? How deep? Make 
a cross section across the Monongahela Valley from New 
England to Portvue. Are the slopes from the divides to 
the river equal ? What are the slopes per mile from the 
divides to the river ? How do these slopes compare with 
those of the Red River on the Fargo, N.D., Quadrangle ? 
With the streams tributary to Lake Michigan in the 
Highwood, 111., Quadrangle ? Which valleys are V- 
shaped ? Which £7-shaped ? 

Wnat large city is shown in this quadrangle ? Note 
the Carnegie Quadrangle to the west. What river 
factors have determined the location of this city ? 

Part II. Early Mature and Young Valleys. El- 
mira Quadrangle, New York-Pennsylvania. — What is 
the general height of the upland ? Of the lowlands ? 
How wide is the valley of Chemung River from Hawes 
Hill to Elmira ? How wide is the valley running through 
Big Flats, Horseheads, and Elmira ? The latter valley was 
formerly occupied by the Chemung River, and this river 
has been forced by an ice blockade to cut its present 
valley. What is the general slope of the valley sides 
of the present Chemung Valley ? Of the former valley ? 
How do the width of valley and slopes of valley sides 
of the abandoned valley compare with the same fea- 
tures of the present valley ? Which valley has the 
most tributary valleys per mile ? How is this to be 
explained ? Do you think that the present Chemung 



WEATHERING, STREAMS AND STREAM VALLEYS 97 

River cut its entire valley or found some of its valley al- 
ready cut ? What explanation does the course of Hendy 
Creek offer ? Does this explanation account for the 
widening of the Chemung Valley west of Elmira ? 
How high would the Chemung River have to rise in 
order to occupy its old valley ? Have Singsing and 
Newtown creeks always had their present lengths? Is 
there any probable relation between the delta at the 
mouth of Seely Creek and the straight course of the 
Chemung River across Elmira ? 

*67. EARLY MATURE TOPOGRAPHY 

Marshall Quadrangle, Arkansas. — In what part of 
the state is this region located ? Into what does the 
Buffalo Fork empty ? What is the average elevation 
of this region ? What is the average depth of valleys ? 
(Buffalo Fork, Middle Fork of Little Red River, East and 
Middle Fork, Illinois Bayou, South Fork of Little Red 
River.) What is the slope per mile of Buffalo Fork below 
Wolem ? Of Middle Fork Little Red River from Boston 
Mountains to the edge of the map? What is the general 
width of the divides in the northern third of the 
region? The middle third? The southern third? In 
general, are the divides flat-topped or sloping ? How 
does the steepness of the valley sides compare with 
those in the Pittsburg region ? Is lateral corrasion 
(lateral planation) prominent in any of the streams ? 



98 MANUAL OF PHYSICAL GEOGRAPHY 

In all of the streams ? Sketch a good type divide. In 
general, do the roads follow the divides or the valleys ? 
Why? 

Are the tributaries well developed ? Is the country 
well drained ? Is the run-off: good ? Compare the 
organization of the drainage with the Fargo, N.D., and 
the Eagle, Wis., regions. Are the divides broadest and 
flattest near or far from the main streams ? Why ? 

*68. MATURE TOPOGRAPHY AND DRAINAGE 

Waynesburg Quadrangle, Pennsylvania ; Pittsburg 
Quadrangle, Pennsylvania. — Compare these quadrangles 
with the Marshall, Ark., Quadrangle as to : width of 
divides, steepness of slopes, dissection, organization of 
streams, run-off, slope of streams, formation of flood 
plains, lateral corrasion. 

Which represents a region in early maturity ? Late 
maturity ? Sketch a region three miles or more square, 
showing a region in early maturity and one in later 
maturity. 

Is a mature region valuable for agricultural pur- 
poses ? Is it densely populated as a rule ? Account 
for Pittsburg and its neighboring cities. Have the 
sudden floods to which the Monongahela and the Ohio 
are subjected any relation to the maturity of topog- 
raphy in their basins? What? 

Refekekce. — The Waynesburg Folio, U.S.G.S. 



WEATHERING, STREAMS AND STREAM VALLEYS 99 

69. A REGION IN OLD AGE 

Caldwell, Kan., Quadrangle. — In general, how 
would you describe the relief of this region — strong or 
weak ? Are the divides broad or narrow, flat- or steep- 
sided ? Are the valleys wide or narrow ? Deep or shal- 
low ? Steep-sided or sloping-sided ? Are there many 
or few tributaries ? Is the drainage well or poorly or- 
ganized ? Are the stream slopes steep or gentle ? Tak- 
ing these features all together, what stage do they indi- 
cate '? The streams have a steeper gradient than would 
be likely in age, but the other features are consistent. 
It is seldom that we can find an area of this size where 
all the features are consistent with any one stage in the 
cycle. Sketch the most typical one, four inches square, 
that you can find. Is the region, as a whole, in early or 
late age ? Which are most typical, the larger or smal- 
ler streams ? How would you distinguish this from 
youthful topography ? 

70. A STREAM IN OLD AGE 

Abilene Quadrangle, Kansas. — The Smoky Hill 
River has many of the features of age. What is its 
depth below the general level of the country ? How 
would you describe the course of the river ? From its 
slopes, would you infer that the current is strong or 
weak ? Are the valley sides steep ? How would you 
expect them to be in this case ? 



100 MANUAL OF PHYSICAL GEOGRAPHY 

71. A REGION IN OLD AGE, RECENTLY REVIVED 

Marietta Quadrangle, Georgia. — This region was 
worn down to a nearly featureless plain (peneplain), and 
then the streams were rejuvenated. The rejuvenation 
is so recent that the main features of aged topography 
still remain. 

In what part of the state is this region ? How far 
and in what direction from Atlanta? Into what does 
the Chattahoochee River flow ? What is the general 
altitude ? How far are the main streams below this 
altitude ? How far are the minor streams ? 

Compare the divides with those of the Fargo, N.D., 
region. How are they similar ? Is the drainage well 
organized ? Sketch the streams of a region three miles 
square south of Dallas. South of Fargo, N.D. (Fargo 
Quadrangle), and south of Waynesburg, Pa. (Waynesburg 
Quadrangle) . Do these regions compare in the matter 
of stream organization ? In the steepness of slopes ? 
In general dissection? 

*72. REVIEW. THE CYCLE OF EROSION 

Chester Quadrangle, Pennsylvania-Delaioare-Neio 
Jersey. — Compare the country on opposite sides of the 
Delaware River as to general altitude, dissection, depth 
and side slopes of valleys, stream slopes and tributaries, or- 
ganization of drainage, divides, their width and slopes. 

In what stage of erosion is each region ? 



WEATHERING, STREAMS AND STREAM VALLEYS 101 
*73. A PENEPLAIN RECENTLY ELEVATED 

Marietta Quadrangle, Georgia. — This area has been 
nearly peneplained and then elevated. What is the av- 
erage elevation ? Imagine yourself looking south from 
Lost Mountain. What kind of a sky line would be 
presented, smooth or rugged ? In what stage of ero- 
sion is most of the country ? What change does the 
topography show in the stage of erosion as you pass 
away from the main drainage lines? Does it become 
more or less youthful ? How is this in a youthful 
topography ? In a mature topography ? How far be- 
low the general surface is the Chattahoochee River ? 
Kenesaw Mountain is a monadnock. How high is the 
main mountain above sea level ? Above the general 
level ? Find several other monadnocks. Are they 
near the main drainage lines ? Why ? Do the roads 
and railroads in general follow the valleys or the 
divides ? 

Reference. — The general region is described in the paper on 
the southern Appalachians, by G. W. Hayes, in the " Physiography 
of the United States." This region is briefly described on page 
326. 

74. A REJUVENATED OR REVIVED RIVER 

Guyandot Quadrangle, West Virginia- Ohio. — At a 
previous period in its history the Guyandot River was 
compelled to aggrade its channel. The old valley is 



102 MANUAL OF PHYSICAL GEOGRAPHY 

filled with silt, sand and gravel scores of feet deep. The 
cause for this is thought to be a glacial obstruction near 
the mouth of the valley, which caused aggradation there, 
and this aggradation caused in turn the gradation up- 
stream. Why ? Later the obstruction was removed, 
and the stream was rejuvenated. Why ? Where 
would such a rejuvenation begin — near the mouth, all 
along the course, or near the head of the stream ? How 
would it differ from the rejuvenation caused by an up- 
lift with tilting ? 

How wide is the valley of the Guyandot at the top? 
At the bottom ? How deep is the old valley ? How 
deeply into the bottom of this valley is the channel of 
the river cut ? Make a profile across the valley about 
two miles above Guyandot. What part of the valley 
has mature slopes ? What youthful ? Do you find 
similar evidences of rejuvenation along Twelvepole 
Creek ? At what places along the Guyandot do you 
find cliffs ? Are they by straight reaches or meanders ? 
Why? 

Terraces. — Make a profile across the Ohio Valley 
near Labelle or near Huntington. How high are the 
terraces above the river ? Are their surfaces level or 
sloping? How far beneath the uplands are they? 

Reference. — This region is described in Professional Paper 
No. 13, U.S.G.S., by W. G. Tight. 



WEATHERING, STREAMS AND STREAM VALLEYS 103 
75. INCISED MEANDERS (ENTRENCHED MEANDERS) 

Huntington Quadrangle, Pennsylvania. — In what 
part of the state is this region ? How far, and in what 
direction, from Philadelphia? From Pittsburg? Lo- 
cate the Juniata River. Into what does it flow ? The 
Raystown Branch of the Juniata River flows between 
two ridges of hard rock. How high are they ? How 
far below the crests of the ridges is the stream in the 
southern part of the map ? In the northern part ? 
What is the height above sea level of the stream near 
Hawn Bridge ? Near Entriken Bridge ? What is the 
total fall of the stream between the two places ? What 
is the average fall per mile along the stream ? In a 
" bee line " f 

Do you think the stream is aggrading, degrading, or 
at grade ? Why ? Do streams usually meander or ag- 
grade with the fall of the Raystown Branch ? This 
stream is thought to have reached a meandering course 
and then have been revived or rejuvenated. After re- 
juvenation, the stream acquired a new energy and began 
to corrade, but still was obliged to keep the meandering 
course which was appropriate to a stream of low slope. 
Looking at the spurs between the meanders, are their 
slopes equal ? Which is the steeper, the upstream or 
the downstream slope ? What is the reason for this ? 
At one time the stream flowed along the 700-foot con- 



104 MANUAL OF PHYSICAL GEOGRAPHY 

tour. Has it since corraded vertically ? Laterally ? How 
far vertically ? How far laterally ? 

Copy the two meanders just below Fink Bridge. Draw 
a dotted line to represent the probable stream course 
along the 800-foot contour. How far has the stream 
moved laterally? Has the meander also moved down- 
stream? What makes you think so? Make a profile 
across the spur below Entriken Bridge, and explain the 
slopes. How could you infer the direction of the stream 
from the spurs alone? In what stage of dissection is this 
region? Do you think the rocks lie horizontal or tilted? 

76. A SUPERIMPOSED STREAM 

Germantown and Norristown Quadrangles, Pennsyl- 
vania. — Trace the Wissahickon Creek (Germantown 
Quadrangle). Compare the width of valley and steep- 
ness of valley sides in the upper and lower portions. 
What is the general elevation of the country in which 
the gorge is cut? In which the upper portion lies? Is 
there any easier course for the Wissahickon to reach 
the Schuylkill? In what kind of rock is the gorge cut 
(Figure 14)? The upper part of the valley? Which rock 
is least resistant to erosion? How does this show in 
different parts of the valley? What explanation can 
be offered for the course of the Wissahickon? 

Harrisburg and Neio Bloomfield Quadrangles, Penn- 
sylvania. — Note the course of the Susquehanna River. 



WEATHERING, STREAMS AND STREAM VALLEYS 105 

Does the river take the easiest course ? Why ? Did it de- 
velop its course on the present topography? Why? When 
the river first started, did it begin its course on this topog- 
raphy or on a plain? Which way must this plain have 
sloped at that time? What other streams in these quad- 
rangles are evidently superimposed? 



WEAK ROCKS 




HARD ROCKS 

Manayunk 



Fig. 14. 
*77. DROWNED STREAM VALLEYS 

Hampton Quadrangle, Virginia. — - In what part of 
Virginia is the quadrangle located? How far, and in 
what direction, from Norfolk? Locate Hampton, Fort 



106 MANUAL OF PHYSICAL GEOGRAPHY 

Monroe, Old Point Comfort. Is the coast smooth or 
indented? On any good map, compare this coast in 
this respect with the coast of Florida, California, Massa- 
chusetts. What is the length, width at mouth, and fall 
per mile of Cheesman Creek, Poquoson River, Back River, 
and Hampton Creek? Do these streams differ in any 
respect from those you have been studying? Is it likely 
that these streams have the velocity or volume to erode 
such wide mouths? If the coast has sunk, how would 
these valleys be explained? How do the Goodwin 
Islands indicate a sinking of this coast? If the coast 
were to rise, how would it change the appearance of the 
larger streams and valleys? Sketch the streams as they 
would then appear. Compare this coast with a good 
map of Chesapeake Bay. What similar features? 

78. FIELD STUDY OF CONSEQUENT, INSEQUENT AND 
SUBSEQUENT STREAMS 

On a newly made lawn or other fresh surface, what 
determines the course of the streams? Streams whose 
courses are determined by slope alone are called conse- 
quent streams. Compare a. valley that is just starting 
with one that is older. Which is longer? Deeper? 
Wider? Give at least four reasons for each answer. 
How do the streams lengthen themselves? Are the 
valleys deepest at head or mouth? Widest? Give all 
the reasons you can. Sketch each stream, showing the 



WEATHERING, STREAMS AND STREAM VALLEYS 107 

tributaries. Do the tributaries have any definite arrange- 
ment? Do they divide and subdivide like the branches 
of a tree? Streams which branch and sub-branch with- 
out any definite guidance by rock structure are termed 
insequent. Their valley pattern is termed dendritic (tree- 
like). 

Observe the streams developing on a plowed field 
or any other surface with a similar structure. Do the 
streams, as a whole, develop across or along the furrows? 
Why? Streams whose courses are largely guided by rock 
structure are called subsequent 

79. MAP STUDY OF CONSEQUENT, INSEQUENT, AND SUB- 
SEQUENT STREAMS AND THEIR ASSOCIATED VALLEY 
PATTERNS 

Hampton Quadrangle, Virginia. — This region was for- 
merly covered by water, but has in recent geological times 
been exposed. Upon this new surface of soft materials 
the streams took their course. What factor determined 
their direction? Which way do the main streams flow? 
Would you say that the tributaries to the main streams 
are also consequent? Sketch a good type consequent 
stream. (In the case of surfaces long exposed to erosion 
it is often very difficult to determine whether a stream 
is consequent or not.) 

Harrisburg Quadrangle, Pa. — Paxton Creek (north- 
east of Harrisburg) is flowing on fairly homogeneous 



108 MANUAL OF PHYSICAL GEOGRAPHY 

rock. Streams like Fishing Creek north of Blue Moun- 
tain, are flowing on rock with a structure shown in 
Figure 24. What kind of rock makes Fishing Creek 
Valley? Blue Mountain? Second Mountain? What 
is the arrangement of the rocks, irregular or in bands ? 
Which stream, Paxton Creek or Fishing Creek, seems to 
follow rock structure ? What term should be applied to 
these streams ? Are the tributaries to Fishing Creek 
insequent or subsequent streams ? Sketch good exam- 
ples of insequent and subsequent streams. 

Stream and Valley Patterns. — Streams and valleys 
like those of Fishing, Stony, and Clark Creeks are said 
to have a parallel or "trellis" pattern. Those like 
Paxton Creek are said to have a dendritic (treelike) 
pattern. How are these terms significant ? Sketch 
good examples of both patterns, not using the examples 
already named. 

Longitudinal and Transverse Valleys. — What val- 
leys are parallel with the ridges ? What valleys cut 
across the ridges ? Which valleys are longitudinal 
(lengthwise) with respect to the ridges ? Which trans- 
verse (crosswise) with respect to the ridges ? What in- 
fluences have these valleys on the direction of roads ? 
Which valleys give access into the ridge belt? Which, 
along the ridges ? What is the best example of a trans- 
verse valley shown on this quadrangle ? 



WEATHERING, STREAMS AND STREAM VALLEYS 109 
*80. STUDY OF A CAftON 

Bright Angel Quadrangle, Arizona. — In what part 
of Arizona is the quadrangle located ? How far from 
the mouth of the river ? What is the general altitude 
of the upland ? How far below the upland is the 
Colorado River ? Has it rapids ? Is the river a graded 
stream ? How wide is the canon from Kaibab Plateau 
to Coconino Plateau ? Make a profile across the canon 
from Grand Canon station northward, using 250-foot 
contour intervals. Where are slopes steepest ? Most 
gradual ? The canon is cut in two kinds of rock, 
crystalline and approximately horizontal sedimentary 
rocks. Can you determine these rocks from the steep- 
ness of the slopes, the evenness of the slopes, and the 
width of the canon cut in them ? How wide is the 
granite gorge compared with the canon that is cut in 
sedimentary rocks ? Which is the younger in stage of 
erosion, the inner or the outer gorge ? Which, in years ? 
Would the relative ages of these gorges have anything 
to do with their steepness and width ? Why do the 
sedimentary rocks form the alternating steep cliffs and 
gentler slopes ? 

How many tributaries has the Colorado River ? Do 
they all have steady streams ? How far from the river 
has headwater erosion proceeded? Compare in this 
respect and in slopes with the region adjacent to the 



110 MANUAL OF PHYSICAL GEOGRAPHY 

Niagara and Ohio rivers. How would climate affect 
these factors ? 

What is a spur ? Dana Butte is a good one. Find 
other examples. Are most of the spurs in this region 
smooth or rough in their horizontal outline ? Keep 
them in mind, and compare with spurs of more humid 
regions. Are the spurs, in general, highest at the point 
(end) or at the base ? Why ? Are the streams numer- 
ous or few ? As a whole, are they steady or intermit- 
tent ? How long is the longest stream on the quad- 
rangle ? Are the springs and wells usually mapped ? 
Why are they on this quadrangle ? What evidences 
as to rainfall do you find ? 

Many photographs of the Grand Canon are taken 
from points on this quadrangle. Locate all you can, 
including the place from which they were taken and 
the area included in the photograph. 

*81. STUDY OF A WATERFALL 

Niagara Falls Quadrangle, New York. — How high 
is Niagara Falls ? How high is the crest above sea 
level ? What shape has the crest of the Horseshoe 
Falls ? Why has it this shape ? (The resistance of the 
rock is practically equal across the crest.) Has the 
crest of the American Falls the same shape ? Why ? 
How wide is the crest of the Horseshoe Falls ? 

The rapids extend from approximately the north end 



WEATHERING, STREAMS AND STREAM VALLEYS 111 

of Goat Island to the crest of the falls. How long are 
the rapids ? What fall have they ? How many feet 
to the mile do they fall ? How wide is the valley 
above the falls ? How deep ? How wide and deep 
below the falls? How would you account for the 
contrast between the valley and the gorge ? 

How long is the gorge ? Make a section about a 
mile above the whirlpool. Is the gorge section box- 



LAKE ERIE 










ESCARPMENT 


LAKE 
ONTARIO 




3 






jjXH 2 CXS^ 33 -^ 


1 








3. 


LIMESTONE. 


2. HARD LIMESTONE. 

Fig. 15. 


t. SHALES. 





like or flaring at top ? Why is it so ? Is it young, 
mature, or old ? 

What change in the direction of the gorge at the 
whirlpool ? How far has the river worn into the Bow- 
man Creek Valley. (There is an old drift-filled valley 
at this point.) Why should the water move here so 
as to make the whirlpool ? What is the fall of the 
river from the foot of the falls to Lake Ontario? 
How much does it fall per mile? Is the river valley 
youthful, above the falls ? Below the falls ? At 
what stage in the cycle of erosion is the surrounding 
country ? 

The structure of the rocks at the falls is shown in 
Figure 15. The Lockport (hard) limestone is harder 



112 MANUAL OF PHYSICAL GEOGRAPHY 

than the underlying shales and limestones. How does 
the rock structure account for the falls ? If the rock 
were homogeneous, how would the falls differ from 
their present form ? Which way do the rocks dip ? 
Will the falls become higher or lower as they recede ? 



CHAPTER IX 

LAND FORMS IN VARIOUS ROCK STRUCTURES — 
STRATIFIED AND HOMOGENEOUS ROCKS 

*82. HILLS AND VALLEYS IN STRATIFIED ROCKS OF VARY- 
ING STRENGTH AND IN HOMOGENEOUS ROCK 

Pikeville Quadrangle, Tennessee. — The general struc- 
ture of the region northwest of the Sequatchie Valley is 
shown in the generalized section, Figure 16. Which 
rock, the sandstone or the limestone, will ordinarily be 
most resistant to erosion ? What kind of depressions do 
you find in the northwest part of the quadrangle ? 
What kind of rock, sandstone or limestone, do these 
indicate ? 

Note the slopes of Little Chestnut Mountain and Milk- 
sick Mountain (northwestern part of quadrangle). Make 
a north-south profile across each. How do their slopes 
contrast ? One is capped with the sandstone and the 
other is not. Which one has the sandstone capping ? 
How do you know ? Welch Knob has the same struc- 
ture as Little Chestnut Mountain. How do its slopes con- 
trast with those of Potts Knob, Burns Knob, and the hills 
to the east of them ? The hills east of Welsh Knob are 
cut in sandstone. Make a generalized statement as to 
the shape of hills cut in homogeneous rock and those in 

i 113 



114 MANUAL OF PHYSICAL GEOGRAPHY 

rock of varying resistance. Illustrate your statement 
with sketches of good types. 

Note how the valley of Caney Fork widens in pass- 
ing from the structure shown in Figure 16 to the 
limestone. About where is the change in rock ? Where 
are steepest valley slopes ? Why ? Note where Cane 
Creek and Glade Creek cut through the overlying 




2. SANDSTONE. I. LIMESTONE. 

Fig. 16. 



sandstone into the limestone. Explain the sudden 
change in the valley section. Pilot Falls marks the 
place where the underlying limestone is reached on 
West Fork. Why should there be falls there? 

83. MOUNTAINS OF CIRCUMEROSION (CIRCUMDENU- 
DATION) 

*Kaaterskill Quadrangle, New York. — Note the well- 
marked chain of peaks and another chain, parallel to the 
first, not so continuous. Note the heights of Plattekill 
Mountain, Indian Head, Twin Mountain, Sugar Loaf 
Mountain, Plateau Mountain, Hunter Mountain. Are 



LAND FORMS IN VARIOUS ROCK STRUCTURES 115 

they uniform ? Do they increase or decrease in height 
in any direction ? Note, also, the heights in the range 
including North Mountain, Stoppel Point, Onteora 
Mountain, Parker Mountain, and East Jewett Range. 
The rock from which these ranges are formed is nearly 
horizontal and mostly sandstone. Since the mountains 
are not caused by differences in rock structure, what 
agents have produced them ? Account for the group 
including High Peak and Roundtop Mountain and Clum 
Hill. Do their heights increase or decrease in any 
direction ? Why should they ? Do the peaks show 
any relation to the tributaries of the streams ? 

84. MOUNTAINS IN LATE YOUTH (CIRCUMEROSION) 

Marshall Quadrangle, Arkansas. — How far, and in 
what direction, from St. Louis ? How high above sea 
level are the Boston Mountains ? How high are they 
above the general level of the valley bottoms ? Are the 
summits flat or sloping ? 

The rock is largely horizontal and stratified. The 
Boston Mountains are a dissected plateau. Is it more 
or less dissected as you approach the White River ? 
Why ? Why is Granny Mountain separated from Cherry 
Flat ? What is the evident origin of the range ending 
in Point Peter ? How will this range change with con- 
tinuous erosion ? How will the Boston Mountains change 
provided there is no interruption to the cycle ? 



116 MANUAL OF PHYSICAL GEOGRAPHY 

85. MOUNTAINS OF CIRCUMEROSION IN MATURITY 

Charleston, West Virginia. — In what part of the 
state is this region ? How do the scale and contour 
interval compare with that of the Marshall, Ark., 
Quadrangle ? The general region here is known locally 
as the " Mountains." Both the Marshall and Charles- 
ton regions are dissected plateaus with nearly horizontal 
stratified underlying rock. Compare the two areas as 
to residual uplands and depth of valleys. Sketch Bos- 
ton Mountains and the three knobs, Grapevine, Hughes, 
and Sugar Camp (Charleston Quadrangle). 

*86. ESCARPMENTS 

Niagara Falls Quadrangle, New York. — What is an 
escarpment ? How distinguished from a cliff ? A hill? 
How high is the Niagara escarpment ? What is its 
average slope per mile ? What is its structure (see Fig- 
ure 15) ? What kind of rock, and what location of this 
rock makes the escarpment ? If the rock underlying 
this area were uniform in resistance to weathering with 
the rock above, how would the form of the escarpment 
probably differ from the present form ? 

References. — The chapter on Niagara Falls, by G. K. Gil- 
bert, in " The Physiography of the United States," 1896 ; " The 
Physical Geography of New York State," Chapter IX, by R. S. 
Tarr, 1902. 



LAND FORMS IN VARIOUS ROCK STRUCTURES 117 
87. ESCARPMENT AND OUTLIERS 

McMinnville Quadrangle, Tennessee,. — In what part 
of the state is this region? What two areas each of 
about equal altitude? What is the average altitude 
of the higher area ? What is this area called ? What 
is the average altitude of the lower area ? What is the 
average difference in altitude between the two areas ? 
Is the slope between them more or less than that of the 
Niagara escarpment ? What is the slope per mile through 
Thaxton (southwestern part of the quadrangle ) ? 

What is the structure of the area (see Figure 17)? 
What rocks make the highland? The lowland? How 



£ 






"? 


1- 
K 




O 


CC UJ 


X 




z 


«! 






m 


3 °- 


i 




1 


] 




1. LIMESTONE 


2. SANDSTONE 





Fig. 17. 



is the structure similar to the Niagara region? How 
different? How is the escarpment made in each case? 
The line of hills, including Butterson Knob, Ben Lomond, 
Mount Cardwell, Turkey Cock, and the unnamed hill east 
of Frank Ferry on the Caney Fork, were formerly part of 
the plateau. Such are called outliers. Does this line 
of hills run straight or does it bend to the east? Does 



118 MANUAL OF PHYSICAL GEOGRAPHY 

the better development of drainage in the region of Falls 
City suggest an explanation of the swerving of the line 
of hills? Short Mountain is an outlier, capped with the 
same kind of sandstone as the plateau. What does this 
indicate as to the former extent of the Cumberland 
Plateau? Some of the following hills are overlaid with 
sandstone, and some are not. Judging by their height 
and slopes, which of the following hills are overlaid with 
sandstone and which are not? Ben Lomond, Short 
Mountain, Little Cardwell, Turkey Cock, Cope Mountain. 
Verify your conclusion from the geological map in the 
McMinnville Folio. 

Reference. — McMiimville Folio, Tennessee, U.S.G.S. 

88. A MATURELY DISSECTED MOUNTAINOUS DIVIDE 

Part I. Mount Mitchell Quadrangle, North Carolina- 
Tennessee. — In what part of North Carolina is this 
region? How far, and in what direction, is it from 
Charleston, S.C. ? How many ranges of mountains are 
there? Is Mount Mitchell an isolated peak or a part of 
a range ? The rocks of this region are largely crystalline 
and not very different in resistance to erosion. The land 
forms, therefore, are largely due to erosion and not to 
rock structure. What is the evident origin of Black 
Mountains? Is its crest even ? Straight? Compare with 
Blue Mountain on the Harrisburg, Pa., Quadrangle. 
(Blue Mountain is due to erosion on folded rocks. It is 



LAND FORMS IN VARIOUS ROCK STRUCTURES 119 

a tilted bed of sandstone with softer rocks on either side.) 
How do the Black Mountains compare with Blue Moun- 
tain in straightness of course and evenness of crest? 

Is there any parallelism of ridges in the Mount Mitchell 
region such as you find in the Harrisburg region? Are 
the different peaks in the Mount Mitchell region at the 
head of streams or between streams? How would you 
explain your answer? How would you account for the 
sudden change in the direction of the Blue Ridge at 
Rocky Mountain? Note the various gaps. What rela- 
tion have they to streams? (Are they between the head- 
waters of streams or in the line of opposite-flowing 
streams?) How would you explain your answer? Trace 
the Blue Ridge. What is its general altitude ? Do the 
ranges change with the changes in direction of streams 
on either side? Do you think that the ranges deter- 
mined the stream courses, or that the streams determined 
the direction of the ranges? What are your reasons? 
Compare the Blue Ridge with the Catskill Mountains 
(Kaaterskill Quadrangle, New York). Which are oldest 
in their development? As erosion proceeds, do you 
think the Blue Ridge will resemble East Jewett Range 
or vice versa f Sketch a good example of a mountainous 
divide. 

References. — Mount Mitchell Folio, North Carolina-Tennes- 
see. The chapter by C. W. Hayes on the Southern Appalachians in 
the " Physiography of the United States." 



120 MANUAL OF PHYSICAL GEOGRAPHY 

Part II. Ishaioooa Quadrangle, Wyoming. — In what 
part of Wyoming is this region? Into what river does 
the Shoshone River flow? The Yellowstone? Where 
do their waters finally reach the sea? What is the height 
of the Absaroka Range? Average width? Is it a fairly 
single ridge, or does it have spurs? Is it a straight ridge? 
What is the evident origin of these spurs? What is the 
height of the crest of Sheep Mesa, Wapiti Ridge, Ishawooa 
Mesa, Needle Mountain, Thorofare Plateau, Trident Pla- 
teau? How do these compare in elevation with Absaroka 
Range? The rock of all, except the northeast corner of 
the region, is crystalline and not notably more resistant 
in one place than another. W 7 hat is the evident origin 
of the range? Why is its crest so crooked? What is 
the origin of its spurs {e.g. Wapiti Ridge)? The region 
is a dissected plateau. How far, in general, have the 
streams cut their valleys into this plateau ? What rem- 
nants are left? Ice erosion has aided in narrowing this 
ridge. The amphitheater-like heads of valleys (cirques), 
such as that at the head of Cabin Creek, are due to ice 
erosion. 

Reference. — Absaroka Folio, Wyoming, U.S.G-.S. 



CHAPTER X 

LAND FORMS AND ASSOCIATED PHENOMENA IN 
FOLDED AND TILTED ROCKS 

*89. YOUNG ANTICLINAL MOUNTAIN AND SYNCLINAL 

VALLEYS 

Ellensburg Quadrangle, Washington. — What is the 
general slope of the elevations, hills, or ridges ? What 
general direction ? How high are the ridges above sea 
level ? Above the valley bottoms ? 

The rock of the region is a basalt. Referring to the 
structure section (Figure 18), how are the rocks ar- 




Fig. 18. 

ranged ? With w^hat structures do the ridges corre- 
spond ? The valleys? Do you think the region has been 
much eroded ? Are the streams consequent ? Why ? 
(Exercises 78 and 79.) 

Reference. — Ellensburg Folio, Washington, TJ.S.G.S. 

121 



122 MANUAL OF PHYSICAL GEOGRAPHY 

90. AN ANTICLINAL MOUNTAIN (UNSYMMETRICALLY 
FOLDED) 

Frosiburg Quadrangle, Maryland-West Virginia- 
Pennsylvania. — Make a profile across Wills Mountain 
from Roberts westward, using the 100-foot contours. 
Are the slopes equal ? What is the eastern slope per 
mile ? The western ? What makes the mountain (see 
structure section, Figure 19) ? What makes the valleys 

BRADDOCKS RUN WILLS MT. POTOMAC RIVER 



i I 1 



4/3/2 




4. SHALE 3. LIMESTONE 2. SHALE 1. QUARTZITE 

Fig. 19. 



on either side ? How high is Wills Mountain ? Would 
an unsymmetrically folded anticline have unequal 
slopes before it was eroded ? Would it after erosion ? 
Does the folding in this mountain agree with the 
slopes ? Could the slopes be due to unequal erosion 
on either side by the Potomac and by Braddock Run ? 
Which of these streams has the largest volume ? The 
greatest fall per mile? Which has eroded the more? 
If the slopes on Wills Mountain are due to the erosion 
of these two streams, would they be as they are at 
present, or would they be reversed ? (It would be un- 
safe to generalize by saying that all ridges with unequal 



LAND FORMS AND ASSOCIATED PHENOMENA 



123 



slopes are due to unsymmetrical folding. Many other 
factors may produce a lack of symmetry in slopes.) 






91. AN" ANTICLINAL VALLEY 

Pikeville and Kingston Quadrangles, Tennessee. — How 
long is the Sequatchie Valley ? How wide ? How 
deep ? Is it variable in width ? How does it compare 
with most valleys in this respect ? How does it com- 
pare with most valleys in straightness? What is the 
rock structure under- 

<- J I 

lying the valley as §| g§ s g 

shown in the general- 
ized section, Figure 20 ? 
Would the sandstone 
or limestone erode more 
rapidly ? In such a 
structure, what kind of forms would result from erosion? 
Make a profile across the valley. Where are its steep 
slopes ? Why would a flat-bottomed valley with steep 
sides result from such a structure ? At what stages 
would a river working in a homogeneous rock have 
such a valley section ? On the west side of the valley, 
do you find any topographic evidence of the limestone? 
What kind of a river is the Sequatchie, insequent or 
subsequent (Exercises 78 and 79) ? What features are 
utilized by the roads out of the valley? 





a 


5 




3° 


} 








I 


EgPji 


Q-^S^?^-^ 


' 




i 




2. SANDSTONE 1 


LIMESTONE 






Fig. 


20. 







124 MANUAL OF PHYSICAL GEOGRAPHY 

Kingston Quadrangle. — Where does the Sequatchie 
River end ? Grassy Cove has about the same structure 
as the Sequatchie Valley. It is a sink hole on a large 
scale, whose waters flow underground into the Sequat- 
chie. About how many square miles are included in 
Grassy Cove ? How does the section across Black 
Mountain differ from that across the Sequatchie Val- 
ley ? Which part of the anticline is in the later stage 
of erosion ? What reasons for the difference in stage ? 
The structure of the Crab Orchard Mountains is the 
same as that of Black Mountain. So far as structure 
is concerned, what name could you apply to them? 
What other examples ? What is the probable ultimate 
fate of Crab Orchard Mountains ? Are they, as a group, 
in youthful, mature, or old stage ? 

Reference. — Kingston Folio and Pikeville Folio, Tennessee, 

U.S.G-.S. 

*92. AN ERODED ANTICLINE WITH MONOCLINAL RIDGES 

Grantsville Quadrangle, Maryland-Pennsylvania. — 
Make a profile from the letter V in the word Savage 
(Big Savage Mountain) to the letter L in the word Salt 
(Salt Block Mountain). 

Note the geological section, Figure 21. What rocks 
are hardest ? What soft ? What does the dip of the 
rocks show the structure to be, horizontal strata, anti- 
cline, or syncline ? What formations make the ridges ? 



LAND FORMS AND ASSOCIATED PHENOMENA 



125 



What, the valleys ? Place beneath your profile the 
symbols for the various rocks, as in Figure 21. (Use 
dots for the sandstones, short straight lines for the 
shales, and small circles for the conglomerates.) 
Which of the formations make two opposite ridges? 
How can they do this? Would two opposite ridges 
be made if the anticline were not eroded ? Why ? Are 



m |- 

< 

X 


o 

Q 

< 




Q 

a 
a 

cc 

\ 


£ O 
a. a 
=) 2 
O 
u. 

1 


o 

CQ 

1 






Z^ 






1 ^ 


^<^\ 








1. 

2. 

8. 


SHALES 

SANDSTONE (POCONO'l 

SHALES 


4. CONGLOMERATE (POTTSVILLE) 

5. SHALES 

6. SANDSTONE 





Fig. 21. 



the slopes of the ridges equal ? If not equal, which 
slope, in general, is steepest ? Which the more gradual ? 
The slopes of Four Mile Ridge have not the same ar- 
rangement as those of the other ridges. Can the work 
of Savage River have an effect here which is not felt 
in the case of the other ridges ? Ridges whose rocks 
have a notably steep dip in one direction are termed 
monoclinal ridges. What are the monoclinal ridges 
in this region ? You will notice that the shales between 
the two monoclinal ridges, Four Mile, Elbow Ridge, and 
Red Ridges, are divided into ridges at approximately 



126 MANUAL OF PHYSICAL GEOGRAPHY 

right angles to the general trend of the anticline. 
Can they be best explained by the structure of the 
rock, or the erosion of the streams? How do they 
compare with monoclinal ridges as to arrangement of 
slopes, continuity, regularity of outline, smoothness of 
crests ? What have you had of similar origin ? The 
Pottsville conglomerate and Pocono sandstone form 
many of the Appalachian ridges. 

93. SYNCLINAL MOUNTAINS 

Staunton Quadrangle, Virginia-West Virginia. — The 
line of elevations, including Great North Mountain, 
Crawford Mountain, Lookout Mountain, Narrow Back 

Mountain, have the 

O . 

•|= same structure (see 

| Figure 22). What is 

their structure ? The 
Pocono sandstone has 
been eroded from most 
of the syncline, except 
in a few patches, which form the mountains named 
above. Why should the sandstone form the mountains? 
Pawpaw Quadrangle, Maryland-West Virginia-Penn- 
sylvania. — Trace Town Hill. What is its length ? 
Average height ? Is the crest flat or sloping ? Is it 
more or less flat near Fifteen Mile Creek and Crooked 
Run ? Why ? What is the structure of Town Hill (see 



r n 




^-~^_ 


Z- 


- 


^"„ 






2. 


SANDSTONE (POCONO) 

Fig. 


22. 




1 


SHALES 





LAND FORMS AND ASSOCIATED PHENOMENA 



127 



Figure 23) ? What rock caps the ridge ? What under- 
lies it ? What makes the ridge flat-topped? On Town 
Hill, about one mile 
southwest of Fifteen \ 

Mile Creek and two 
miles northwest of this 
creek, the overlying 
Pocono sandstone has 
been removed by erosion. 
What effect has the 
absence of the sandstone on the crest of Town Hill ? 
The crest of Town Hill has a sandy soil and the sides 
have a sandy loam. How would you account for 
these soils ? 




2. SANDSTONE (POCONO) 

Fig. 23. 



*94. ERODED SYNCLINES AND MONOCLINAL RIDGES 

Ilarrisburg and New Bloomfield Quadrangles, Penn- 
sylvania. — What are the prominent features of the 
region ? Do they arise from horizontal or folded strata ? 
What makes you think so ? Trace Blue Mountain. 
How high is it ? In the average, how wide is its 
crest ? Is it highest near the Susquehanna River ? Why ? 
Trace Second Mountain. What is its name west of the 
Susquehanna River? Does it die out or turn back on 
itself ? Trace it as far as you can, and note the differ- 
ent names that the same mountain bears. What is the 
average height of Blue Mountain, Second Mountain, 



128 



MANUAL OF PHYSICAL GEOGRAPHY 



Third Mountain, and Peters Mountain ? What is the 
structure of the ridges on the Harrisburg map (see Fig- 
ure 24) ? What three rocks make the ridges ? What 
two of these have you noted before ? Which one of 
the hard rocks makes Peters Mountain and Second 
Mountain ? How can the one formation make the two 
ridges ? What formation makes Third Mountain ? 



Y 


1 I 


1 


\ 


^\ 3 




4 x 3 y 


' 2 / l 



6. COAL MEASURES (SANDY SHALES AND POTTSVILLE CONGLOMERATE) 

6. SHALES 4. SANDSTONE (POCONO) 3. SHALES 

2. SANDSTONE 1. LIMESTONE 

Fig. 24. 

Classify Blue Mountain, Second Mountain, Third Moun- 
tain, and Peters Mountain, as to whether they are 
anticlinal, synclinal, or monoclinal ridges. The slopes 
of the ridges here are not so characteristic of their struc- 
ture as they are on the Frostburg and Grants ville maps, 
owing largely to the thorough dissection by the streams. 
Why should this make a difference in characteristic 
slopes ? 

95. A SYNCLINE WITH PITCHING AXIS 

Harrisburg and New Bloomjield Quadrangles, Penn- 
sylvania. — You will note from the structure section that 



LAND FORMS AND ASSOCIATED PHENOMENA 



129 



Second Mountain and Peters Mountain are on opposite 
sides of a syncline, and that they meet in the New Bloorn- 
field Quadrangle. Also, that Third Mountain comes to a 
point in the same direction. Before working out the 
reasons for this behavior, note Figure 25. It repre- 
sents a syncline with the axis xx dipping towards the 
bottom of the page. 
That is, the syncline, as 
a whole, is higher above 
sea level at its north 
than at its south end. 
What would be the 
effect upon the distance 
between the outcrops of 
the hard layers HH(re^>- 
resented by the line dd) 
if the syncline were 
eroded down to the line aal Would they be wider 
apart or nearer together ? What would be the effect 
if the syncline were eroded to bb ? 

If the axis of the syncline were horizontal, the out- 
crops HH would be at equal distances apart. Why ? 
As the syncline in Figure 25 is eroded, at which end 
will the outcrops HH approach each other most ? 
At what end will they approach each other least ? 
After long erosion the outcrops HH would have the 
position shown in Figure 26. Why? Make a general 




Fig. 25. 



130 



MANUAL OF PHYSICAL GEOGRAPHY 



rule for determining the pitch of a syncline by the way 
the outcrops approach each other. Illustrate, if pos- 
sible, with block diagrams (like Figure 25) or by 
sketches. 

With this principle in mind, determine the following 
questions : Why do Second and Peters mountains 

unite ? Why do they point south- 
westerly? Which way does 
the axis of the syncline dip, 
northeast to southwest or vice 
versa? Why is Third Mountain 
pointed ? Why does it widen to 
the eastward ? Taking the dia- 
gram, Figure 25, has the syncline 
of which Peters Mountain and 
Second Mountain are a part reached the line aa or 
bb ? Which lines has the level part of Third Mountain 
reached ? 

The valley of Cove Creek, locally called " The Cove" 
(New Bloomfield Quadrangle), has been called a " canoe 
valley." What appropriateness has this name ? Ex- 
plain the origin of Cove Creek Valley. 




Fig. 26. 



96. LAND FORMS RESULTING FROM THE EROSION OF A 
PITCHING ANTICLINE 

Staunton Quadrangle, Virginia-West Virginia. — 
What are the heights of Walkers Mountain and Side- 



LAND FORMS AND ASSOCIATED PHENOMENA 



131 



ling Hill at their highest points? At their lowest 
points ? What kind of structure have they (see Fig- 
ure 27) ? What kind of rock makes them ? When an 




Fig. 27. 



anticline is eroded, do its outcrops recede from each 
other or approach each other (see Figure 28) ? How 
does this compare with a syncline ? The axis in Fig- 





Fig. 28. 



Fig. 29. 



ure 28 is pitching or dipping toward the top of the 
page. As the anticline is eroded, will it become nar- 
rower or broader equally at both ends ? As erosion 
proceeds, the outcrops, HH in Figure 28, will finally 
have the position shown in Figure 29. Why? Has 



132 



MANUAL OF PHYSICAL GEOGRAPHY 



the anticline which makes Walkers Mountain and Side- 
ling Hill a pitching axis ? Why ? Which way does it 
pitch? Illustrate by a block diagram. 

Why are there no monoclinal ridges as in the Grants- 
ville, Md., Quadrangle ? What stream in the vicinity 
is a good example of a subsequent stream ? 

New Bloomfield and Harrisburg Quadrangles, Penn- 
sylvania. — Trace Half Falls Mountain. What is its 

shape ? Do you think 
§ 2 « it extends into or 

1 £ | across the Susque- 

— «r * 

hanna River ? What 
is the horizontal out- 
line of the mountain ? 
What is the structure 
of Half Falls Moun- 
tain and the adjoining ridges (see Figure 30) ? Has 
the folding a horizontal or a pitching axis ? How do 
you know ? Which way does the axis pitch ? How 
do you know ? Classify and give your reasons as to 
whether Half Falls Mountain, Mahanoy Ridge, and 
Hickory Ridge are anticlinal mountains or monoclinal 
ridges. 




1. SANDSTONE 



3. SANDSTONE 



97. STREAM ADJUSTMENT IN FOLDED STRUCTURE 

New Bloomfield Quadrangle, Pennsylvania. — Trace 
the western Fishing Creek which flows into the Susque- 



LAND FORMS AND ASSOCIATED PHENOMENA 133 

hanna at Marysville. Note the tributaries. What is 
notable in the headwater regions of the longer tribu- 
taries ? Do all the longer ones show this peculiar pat- 
tern ? Note Trout Run. Through what kind of rock 
is its lower course cut (see Figure 31)? Its upper 
course? Why, then, does Trout Run bifurcate in its 
upper course ? Why do not the shorter tributaries 
bifurcate ? As Trout Run extends its headwaters along 




1. SHALES 2. SANDSTONE 3. SHALES 4. SANDSTONE 5. SHALES AND SANDSTONE 
6. SHALES AND SANDSTONE 7. SANDSTONE (POCONO) 8. SHALES 

Fig. 31. 

the belt of weaker rock, it will ultimately capture or be 
captured by other similar tributaries. In this way the 
valleys will be opened out. When the streams of a 
country are flowing on the weaker rocks they are said 
to be adjusted. Is the adjustment in this region com- 
plete ? Is it well advanced ? When would fairly com- 
plete adjustment come, in youth or in maturity ? Sketch 
an example of complete stream adjustment; of an in- 
complete adjustment. 



134 



MANUAL OF PHYSICAL GEOGRAPHY 



*98. STREAM CAPTURE IN FOLDED ROCKS 

Harper s Ferry Quadrangle, Virginia- West Virginia- 
Maryland. — This region formerly was peneplained, the 
peneplain sloping southeasterly. Upon this peneplain 
the Potomac, Beaverdam Creek, and other streams 

were established. When 
these streams began to cut 
through the Blue Ridge, 
which stream, the Potomac 
or Beaverdam Creek, would 
cut the faster? Why? Which 
tributaries, those of the Po- 
tomac or Beaverdam Creek, 
would extend faster along 
the weak rocks of the 
present Shenandoah Valley 
(Figure 32) ? The Shenan- 
doah began as a short tribu- 
tary to the Potomac. It 
extended rapidly southwest 
along the belt of Weak Rocks. (Give two good reasons.) 
The Shenandoah captured the headwaters of Beaverdam 
Creek. Why should it do so? Prom the above facts, 
explain Snickers Gap and the two streams heading from 
the gap. How deep is the gap ? How high above 
the Shenandoah Valley is the floor of the gap ? How 




Fig. 32. 



LAND FORMS AND ASSOCIATED PHENOMENA 135 

long is the gap? Is it a "wind gap" or a "water 
gap " ? Find examples of a wind gap and a water 
gap in this map, and sketch them. Draw sketches to 
illustrate the process of stream piracy in connection 
with Beaverdam Creek. What factors affect stream 
capture here that are not operative in the Kaaterskill, 
N.Y., region (Exercise 64) ? 

What changes in the width of the Potomac Valley and 
in valley slopes above and below Harper's Ferry? Why? 

What strategic importance had Harper's Ferry in the 
Civil War? What is the geographic basis for this im- 
portance ? 

99. THE EFFECT OF A CHANGE IN DIP UPON THE 
WIDTH OF OUTCROP 

Part I. Huntington Quadrangle, Pennsylvania. — 
What is the height of Allegrippis Ridge ? What is the 
structure (see Figure 33) ? 
The ridge is composed of 
sandstone and conglomer- 
ates in this region. The 
dip of the rocks making 
Allegrippis Ridge, in Hopewell Township, is about 38°, 
and in Juniata Township, about 20°. What is the 
width of the ridge in Hopewell Township across the 
letter L in Allegrippis ? In Juniata Township about 
two miles north of Hawn Bridge ? 




Fig. 33. 



136 MANUAL OF PHYSICAL GEOGRAPHY 

Which, makes the wider outcrop, the lower dip or the 
higher dip of a bed ? Why ? Draw to illustrate. 

Part II. Briceville Quadrangle, Tennessee. — The 
rocks forming Black Oak Ridge dip southeasterly, but 
the amount of dip varies. Judging from the varying 
width of the ridge, where is the dip steepest ? Where 
least steep ? Draw diagrams to illustrate. 

With a given structure, what dip would give a mini- 
mum outcrop ? A maximum outcrop ? 

Reference. — The Huntington Quadrangle is described in the 
volume on Huntington County, Second Geological Survey of 
Pennsylvania. The Briceville region is described in the Brice- 
ville Folio, U.S.G.S. 

100. PENEPLAINS 

Harrisburg Quadrangle, Pennsylvania. — It is be- 
lieved that two ancient peneplains are to be found in 
this region. If you were to fill up the valleys in the 
lowland south of Blue Mountain, what kind of a surface 
would you have, smooth or rough ? How high above 
sea level ? How does this height agree with the eleva- 
tion of the valleys between the larger ridges ? 

What would be the elevation of such a plain in the 
valley north of Peters Mountain? (This is considered 
as belonging to the peneplain in the vicinity of Harris- 
burg.) Which way does the peneplain slope ? How 
much below it is the valley of Paxton Creek cut ? Of 
Powell Creek ? Is the incised meandering valley of 



LAND FORMS AND ASSOCIATED PHENOMENA 137 

Conodoguinet Creek of any significance in connection 
with this peneplain ? 

If you imagine the valleys between the ridges to be 
filled, what kind of country would you have ? How high 
above sea level? How high above the peneplain in the 
Harrisburg region ? This peneplain, the remnants of 
which are the ridges, has been called the Kittatinny 
Peneplain. How far below this peneplain has the 
Susquehanna cut its valley ? How would the course of 
this river across the mountains be explained ? Why 
have the ridges been preserved ? The lower peneplain 
is discussed by M. B. Campbell, Bull. G.S.A. Vol. 14, 
pp. 277-296. 

Supplementary Questions. Harrisburg Quadrangle, 
Pennsylvania. — How high above the river is the ter- 
race upon which most of Harrisburg is built ? How 
wide ? Can you trace the terrace on the west side of 
the river ? Why ? Trace the course of Paxton Creek. 
At about what angle does it enter the Susquehanna 
Valley ? The Susquehanna River ? Did the river 
ever cover the present terrace ? At that time do you 
think Paxton Creek followed its present course par- 
allel to the river ? Why ? What is the probable 
reason why it does so now ? Find examples of wind 
gaps. Of water gaps. What contrast in the arrange- 
ment of roads in the ridge region and in the plain 
region? 



138 MANUAL OF PHYSICAL GEOGRAPHY 

*101. STAGE OF EROSION IN TOPOGRAPHY DEVELOPED 
ON FOLDED ROCKS 

(In the Raritan Quadrangle, use only the region northwest of the Fox Hill 
Range.) 

Ellensburg, Wash., Harrisburg, Pa., and Raritan, 
N.J., Quadrangles. — Compare the three regions as to 
dissection, adjustment of streams, sharpness of crests. 
Sketch type examples. (In the Raritan region, the 
drainage north of 40° 50' is disorganized by glaciation.) 
Classify them, and give full reasons, into youthful, ma- 
ture, and late mature regions. 

102. MONOCLINAL SHIFTING 

What is a monocline ? It may be illustrated by 
Figure 34. The rocks are inclined. Which way do 

they dip in the figure ? As 
the surface AB is eroded, 
will the outcrops H and S 
remain in the same relative 
position, or will they migrate ? What will the positions 
of the outcrops be when the surface is eroded to XX. 
Draw. Does the outcrop of monoclinal strata migrate 
with or against the dip of the strata ? Such shifting 
is termed monoclinal shifting. 

Holyoke Quadrangle, Massachusetts. — The Holyoke 
Range is of trap rock, with a structure shown in Figure 
34. The trap rock H is overlaid and underlaid by 




x 



LAND FORMS AND ASSOCIATED PHENOMENA 



139 



softer sedimentary rocks. All the rocks in the vicinity 
dip eastward. At several points, the range is crossed 
by faults (dip faults). The region on one side of the 
fault has been elevated, as in Figure 35. As this up- 
thrown block is eroded, which way will the outcrop H 
migrate ? After the upthrown block is eroded even 





^ 


vs 


Vh 


//V 




AY 


<K 







H 




H 





Fig. 35. 



Fig. 36. 



with the other block, will the outcrop of H in each 
block meet ? If not, on which block will H be most 
easterly? The result, after erosion, would be as in 
Figure 36. If you had the converse problem of deter- 
mining which is the upthrown side, by knowing which 
side showed a migration with the dip of the rock, how 
would you determine it ? For example, south of Shel- 
don Hill the Holyoke Range has shifted somewhat 
eastwardly. Which is the upthrown side? Draw to il- 
lustrate. 

*103. "HOG BACKS" 

Denver Quadrangle, Colorado. — Two great features 
are shown here, the Great Plains and the eastern front 

How high above sea level 



of the Rocky Mountains. 



140 MANUAL OF PHYSICAL GEOGRAPHY 

are the plains ? How high is the Rocky Mountain 
Range, shown on the western edge of the map? Locate 
Denver, South Platte River, Golden. South of Golden 
are ridges known as " hog backs." How high, in gen- 
eral ? What is the average width ? They are caused 
by outcrops of Dakota sandstone (see structure section, 




I. CRYSTALLINE ROCKS 2. SHALES AND SANDSTONES 

3. SANDSTONE (DAKOTA) 4. SANDSTONES AND SHALES, 

6, 6. SHALES, SANDSTONES AND CLAYS 

Fig. 37. 



Figure 37). What is the structure — anticlinal, syn- 
clinal, or monoclinal ? 

Make a profile across the ridge west of Littleton 
(south of Denver). Which slope is steeper ? Why ? 
Which, less steep ? Why ? What seems to account for 
the breaks in the ridge ? The parallel ridges near Deer 
Creek are due to a hard layer in the stratum under- 
lying the Dakota sandstone (Wyoming formation). 
Why is there a valley between the hog backs and the 
mountains? The Table Mountains, west of Denver, are 
capped by basalt. How do their slopes differ from 
those of the ridges ? 

Irrigation. — Note the irrigation canals. How do 
their courses differ from the average stream course ? 
Do you find any canals that are parallel to the con- 



LAND FORMS AND ASSOCIATED PHENOMENA 141 

tours ? What is the greatest distance from the stream 
that any canal extends ? What advantage for irriga- 
tion does this region have ? 

Reference. — The region is described in Monograph 27, 
U.S.G.S. (Geology of the Denver Basin). 

104. A CUESTA 

Trenton, N.J. -Pa., and Navesink, N.J. -NY., Quad- 
rangles. — In what part of New Jersey is this area? 
Draw a profile, using only 100-foot contours, from Silver- 




1. SOFT ROCKS 2. HARDER ROCKS 3. SAND 4. CRYYTALLINE ROCKS 

Fig. 38. 

ton (southeastern part of Navesink Quadrangle) through 
Debow Hill to Princeton. Use the scale of one inch to 
the mile, and paste the parts of your profile together 
so as to make it continuous. Below your profile, draw 
to show the kinds of rock underlying the country (see 
Figure 38). What is the arrangement of the rocks east 
of Princeton ? Which way do they dip ? What rocks 
make highlands ? What, lowlands ? 

Explain the origin of Debow Hill. Is this hill 
isolated, or is it a portion of a serrate ridge ? Are the 



142 MANUAL OF PHYSICAL GEOGRAPHY 

slopes of this ridge equal ? Which direction is the 
steep slope ? The gentle slope ? How are these slopes 
associated with the structure (e.g. Debow Hill) ? Would 
you be likely to have such slopes if the rocks were 
homogeneous? Would you, if the dip of the rocks 
were vertical? Why? A cuesta is a ridge resulting 
from such a structure. It has a gentle outer slope 
and a steep slope facing the inner lowland. Trace the 
cuesta and inner lowland. How many rivers occupy 
the inner lowland? Name them. What large river 
occupies it in part? 



CHAPTER XI 

LAND FORMS DUE PRIMARILY TO FAULTING AND 
VOLCANISM 

105. A FAULT SCARP BUT LITTLE DISSECTED 

*Part I. Mount Trumbull, Ariz., Quadrangle. — In 
what part of Arizona is this quadrangle ? Hurricane 
Ledge is caused by a fault. Which side is upthrown ? 
Which, downthrown ? What is the average height of 
Hurricane Ledge? Where does it end? 

What can you infer as to the rainfall of this region ? 
What are your reasons ? What effect has this rainfall 
on the dissection of the fault scarp ? 

In what general physiographic division of the United 
States is this region ? 

Part II. A Dissected Fault Scarp. Austin, Tex., 
Quadrangle. — What two divisions of the regions so far 
as altitude is concerned ? How much of the quadrangle 
lies at, or below, 750 feet altitude ? How much above 
1000 feet altitude ? Between these two altitudes are a 
series of parallel faults. Trace the belt between these 
two altitudes across the map. How much is the slope 
per mile, on the average, in the fault zone ? Has the 
faulting been recent? Why? 

143 



144 MANUAL OF PHYSICAL GEOGRAPHY 

The escarpment is known locally as the Balcones, and 
the region west is known as the Mountains. Why is 
the term mountains applied to the region west of the 
Balcones? What difference in dissection is there be- 
tween the mountains and the plain ? How do the hills 
differ in the two areas in slopes and height ? How does 
the width of the Colorado Valley differ in the two divi- 
sions ? 

What would account for the contrast in distinctness 
of the fault scarps in this region and in the Hurricane 
Ledge ? 

*106. BLOCK MOUNTAIN AND RIFT VALLEY 

Alturas, CaL, and Long Valley, Nev., Quadrangles. — 
In what part of their respective states are these areas ? 
How long is Warner Mountains ? How high above sea 
level ? How broad is the mountain ? Does it most 
resemble the Catskill, Rocky Mountains, Col., Mount 
Mitchell, or the Appalachian Ridge (Harrisburg, Pa., 
region) type ? Make a profile along parallel 41° 30'. 
Are the slopes equal ? Where do the slopes begin to 
become steeper as you go from the crest toward the 
west? What is the slope per mile from the crest to 
Alturas Hill ? To Surprise Valley ? Change these 
slopes into degree reading (either by construction and 
measurement of the angles, or by trigonometry). Is 
the crest sharp? What is the structure underlying 



LAND FORMS 145 

these mountains (Figure 39) ? The rock is of rather 
homogeneous crystallines. How does the structure ex- 
plain the slopes ? The crest ? 

A fault runs parallel to the base of the mountains, 
and some of the faulting is so recent that alluvial cones 
have been faulted. Which is the upthrown side of 
the fault ? The downthrown side ? Which streams, 
the eastward flowing or the westward flowing, have 
the longest 

° WARNER SURPRISE 

9 "\TT1 MOUNTAINS VALLEY 

course i Why ( J-^\ 

The steepest ^^—- ~-""^ \ 

slopes? Why? fji 

Compare the dis- ' -? ' 

Fig. 39. 

section oi the 

fault scarp with that in the Austin, Tex., region. 

Surprise Valley. — From the diagram, determine the 
origin of Surprise Valley. Is there an outlet for its 
drainage ? Why, then, do not the lakes fill up the 
valley ? Why should the middle lake be called Alkali 
Lake ? How far is the valley below the uplands ? 
Which fault scarp, east or west, has the greatest height ? 
Which is most dissected ? Which is most distinct ? 

Long Valley has an origin similar to that of Surprise 
Valley. How far is the valley below the uplands ? 
Make a diagram illustrating its origin. How would 
you distinguish it from a normal erosion valley ? How 
would you explain the drainage? What kind of lakes 



146 



MANUAL OF PHYSICAL GEOGRAPHY 



are those east of Alkali Lake ? What does the name of 
Alkali Lake suggest as to the climate ? Note the eleva- 
tion about four miles east of Alkali Lake. What origin 
do its slopes suggest ? Illustrate by a profile and dia- 
gram. 

107. REVIEW. EROSION FORMS ON FOLDED AND 
FAULTED STRUCTURE (STRIKE FAULT) 

Gadsden Quadrangle, Alabama. — Note Red Mountain 
and Straight Mountain. Do they seem to unite? Do 
you think they belong to one structure or to different 
structures ? Why ? Do they unite in a point ? Where 
else have yon seen ridges meeting in a point ? What 
does this indicate, if the structure is synclinal ? If anti- 
clinal ? Can you infer, by the slopes, what the structure 
is? Why do the streams make any such inference un- 
safe? Does Red Mountain have any peculiar topog- 
raphy ? How does it differ in topography from 
Straight Mountain ? What is the structure (Figure 40)? 




1. LIMESTONE 2. CHERTY LIMESTONE 3. LIMESTONE 

Fig. 40. 



4. SANDSTONE 



LAND FORMS 147 

Which way does the axis probably dip ? What rock 
makes the unnamed ridge west of Red Mountain? 
What influence on the slopes of this ridge has the dip 
of the sandstone? What rock makes Red Mountain? 
How far does the knobby topography of Red Mountain 
extend ? A fault parallel to Straight Mountain begins 
east of Aurora and runs southwest. This has its down- 
thrown side on the west, and the bed that made Red 
Mountain has been carried down, while the same bed 
that makes the ridge west of Red Mountain makes 
Straight Mountain. How is the fault indicated by the 
topography ? 

*108. A VOLCANIC MOUNTAIN 

Shasta Special Quadrangle, California. — Mount 
Shasta is a young volcanic mountain which has not 
as yet been greatly eroded. Various coulees are found 
about the mountain, where lava has escaped. Among 
them are Lava Park, and lava flows at various locali- 
ties. The lava from the coulees rapidly cooled and 
hardened quickly before the flow could spread out. In 
general, therefore, the margins of these flows are bounded 
by rather steep cliffs. Why ? Note the lava flow in 
the northeastern corner. This had its origin at about 
10,000 feet. Where is its margin? How long is the 
coulee ? Trace, likewise, the limits of the lava flow at 
Lava Park. Note an unnamed lava flow about five 



148 MANUAL OF PHYSICAL GEOGRAPHY 

miles southwest of Shastina. Beginning with. Bear Butte, 
there is a line of hills running up the mountains, in- 
cluding Cinder Cone, Gray Butte, and Red Butte, 
These are all lava cones except the two cinder cones. 
Trace the routes to the summit from the railroad 
near Sisson. Why does the right-hand route zigzag up 
the mountain beyond Mud Creek ? Why does the rail- 
road zigzag in the southwestern part of the map ? 

Reference. — The chapter on Mount Shasta by J. S. Diller in 
" The Physiography of the United States." 

*109. A DISSECTED VOLCANIC MOUNTAIN 

Marysville Quadrangle, California. — Marysville Buttes 
is a partly dissected volcano, with a central core of igne- 
ous rock and a surrounding zone, largely composed of 
tuffs and breccias derived from the central core. Copy 
the general outline of the Buttes. (This can well be 
done through transparent tracing paper.) The inner 
core of hard volcanic rocks may be outlined roughly as 
follows : from the letter A in Marysville to a point 
about two miles north of the letter S and thence to the 
letter L in the same word ; from L to the letter E in 
the word Buttes ; from this point to the letter B in the 
same word, and thence to the point of beginning. This 
will give the general area of hard rock. (If the Marys- 
ville Folio is at hand, use the geological map.) Outside 
of this area is the zone of derived and softer rock. 



LAND FORMS 149 

Compare the two zones as to erosion. What average 
height have Marysville Buttes ? What average diame- 
ter ? What is the slope per mile of the sedimentary 
zone? Of the igneous zone? Explain the difference. 

Reference. — Marysville Folio, U.S.G.S. 

110. LACCOLITHIC MOUNTAINS 

Henry Mountain Quadrangle, Utah. — In what part 
of the state is this area ? How far, and in what direc- 
tion, from Salt Lake City ? The Henry Mountains are 
good examples of laccolithic mountains. Compare the 
peaks with mountains of circumerosion ; with folded 
mountains. How high are the four principal peaks 
above sea level ? Above the general level of the pla- 
teau ? Are the slopes steep ? Are they more steep in 
one direction than in another ? Considering the origin 
of these peaks, is there any reason why they should 
have a round, rather than a linear, shape? Mount Hil- 
lers has a main laccolith with two smaller ones to the 
northeast. Find the two hills made by these. How 
high are they ? 

Eeference. — Report on the Geology of the Henry Mountains, 
C. K. Gilbert, U.S.G.S. 

•111. A VOLCANIC NECK 

Austin Quadrangle, Texas. — Pilot Knob is an exam- 
ple of a volcanic neck. What is its height ? Diameter ? 



150 MANUAL OF PHYSICAL GEOGRAPHY 

About what is its area ? Why should Pilot Knob 
stand above the surrounding country ? An outcrop 
of volcanic materials is found near Bluff Springs to 
the west. At least how far froni the volcano has the 
eruptive material been spread in this case ? Might it 
have been carried farther and leave no record ? 

Reference. — Austin Folio, U.S.G-.S. 

112. TOPOGRAPHY DUE TO A DIKE 

New Bloomfield Quadrangle, Pennsylvania. — Iron- 
stone Ridge (southern part) is caused by a dike. Is its 
rock harder or softer than the surrounding rock ? How 
high above the adjacent country? Trace the ridge as 
far as you can. What is the probable significance of 
the name of the ridge ? What political boundary does 
the ridge form ? 

*113. LAVA CONES AND CINDER CONES 

The steepness of slope of a cinder cone is from 30° 
to 40°. That of a lava cone made by very fluid lava 
may be as low as 6° (Mauna Loa, Hawaiian Islands). 
Why should there be so great a difference ? Using the 
same scale, construct an angle of 6° and 30°. Show 
the same by an ideal contour drawing of the two cones, 
using the same scale and contour interval. 



LAND FORMS 



151 



*114. A SILL 



Harlem Quadrangle, New York-New Jersey. — The 
steep cliff facing the Hudson on its western side is the 
Palisades (read description). It is a sill which has been 
elevated and tilted toward the west (see structure section, 




1. SHALES AND SANDSTONES 2. CRYSTALLINE ROCK (DIABASE) 

Fig. 41. 

Figure 41). How high is the crest above the river? Make 
a profile across the Palisades. What is the slope per mile 
of the Palisades to the Hudson ? To the westward ? 
What reasons are there for the steep eastward slope? 
For the more gentle westward slope ? To which of the 
formations is the Palisades due ? 

Beference. — New York City Folio, TJ.S.G-.S. 



CHAPTER XIT 

GLACIATION 

*115. ALPINE OR MOUNTAIN" GLACIERS 

Shasta Special Map, California. — Where is Mount 
Shasta ? How far, and in what direction, from San 
Francisco ? How many glaciers can you find ? Are 
they all united ? Where are some united, at their 
heads or at their margins ? How would you explain 
this ? Why is not the top of the mountain covered by 
ice ? Does the ice occur for the most part in valleys or 
on ridges ? Why ? How deep is the valley leading 
away from Wintun glacier (near the foot of the 
glacier) ? 

Are the glaciers equally long ? Equally broad ? 
Equally large ? About how many square miles in 
Hotluin glacier ? Is there more ice in any one direc- 
tion than in another? How would this be explained 
by (1) direction of slopes, (2) catchment area ? What 
is the lowest limit of the ice on the north side ? On 
the south side ? How high is Mount Shasta ? 

116. CIRQUES (ALPINE GLACIATION) 
Gilbert Peak Quadrangle, Utah— Wyoming . — In what 
part of Utah is this quadrangle located? How far, 

152 



GLACIATION 153 

and in what direction, from Salt Lake City? How 
high are the Uinta Mountains ? How high above the 
average level of the surrounding country ? Would you 
describe the drainage as youthful or mature ? Do the 
lakes all have outlets ? This region shows good illus- 
trations of cirques (amphitheater-like openings at the 
head of valleys). The one containing Lake Atwood 
(central part) is a good example. How many cirques 
can you find ? What is the average height at which 
they are found? What drainage features are usually 
found in their basins ? About how many square miles 
in the cirque containing Lake Atwood ? Make a pro- 
file through this cirque to the Uinta River. In what 
part of its course is the valley steepest ? Least steep ? 
Where is the valley widest ? What is its slope per mile 
in the fairly level portion ? In the steep portions? Com- 
pare the profile with that of the streams in Exercises 65, 
66, 67. How do their upper, middle, and lower courses 
compare in slope, steepness of valley sides, and width 
of valleys? The small isolated lakes without outlets 
occur in the moraines built by the glaciers. How high 
upon the mountains do they occur? Do you think 
that cirques are the result of constructive or of destruc- 
tive work of the ice ? Why ? 



154 MANUAL OF PHYSICAL GEOGRAPHY 

*117. U-SHAPED AND HANGING LATERAL VALLEYS 

Telluride Quadrangle, Colorado A valley glacier 

extended down the valley of the Lake Fork of the San 
Miguel River. Make a profile across this valley at 
Belt Ranch and one across the valley of Bilk Creek, 
east of Diamond Hill, using the same scale in each 
profile. How do these profiles compare in shape ? 
Which is F-shaped ? Which is 27-shaped ? Which 
valley do you think has been shaped by ice erosion? 
Which, by water erosion ? 

Make a profile of Vance Creek. Where are its 
steepest slopes ? Do normal streams have their steep- 
est slopes at their heads or at their mouths ? Vance 
Creek Valley is an example of a hanging valley. How 
high does it "hang" above its main valley? How do 
normal streams enter their main streams, at grade or 
hanging? Explain the behavior of Vance Creek. 
Find and sketch other examples of a main Z7-shaped 
valley and its hanging lateral valley. 

Compare the valley sides of the San Miguel River with 
those of the Chattahoochee River (Marietta Quadrangle, 
Georgia) and of the Buffalo Fork of the White River 
(Marshall Quadrangle, Arkansas). How do they com- 
pare in general smoothness of outline ? In the sharp- 
ness of their spurs ? Sketch good examples. Explain 
the contrasts. 



GLACIATION 155 

Compare the number of towns with, those of the Mar- 
shall, Ark., and Marietta, Ga., regions. How would 
you account for the population of the sterile Telluride 
region ? 

Reference. — Telluride Folio, U.S.G-.S. 

•118. MARGINAL MORAINES 

Islip Quadrangle, New York. — In what part of 
Long Island is this quadrangle situated ? How wide 
is the island here ? How many belts of highland ? 
What is the general height of each belt ? How many 
belts of lowland ? What is the general height of 
each ? Does the southern lowland hold its elevation, 
or is it sloping? Make a profile across the island 
through Babylon. What is the slope (per mile) of the 
southern lowland ? Which have the most even surface, 
the highlands or the lowlands ? Compare the hydrog- 
raphy of the two. 

There are two moraines and two outwash plains run- 
ning across Long Island. The moraines have consider- 
able till, while the outwash plains are composed largely 
of sand and gravel. Can you identify the moraines by 
their greater altitude ? Which feature has the greater 
number of undrained ponds ? Does this fact have any 
relation to the composition of the moraine ? Are there 
any depressions without water in them ? Where are 
they situated ? How far above sea level is the surface 



156 MANUAL OF PHYSICAL GEOGRAPHY 

of Lake Ronkonkoma ? How much below the general 
altitude of the moraine is this surface ? How many 
streams on the southern outwash plain ? What rela- 
tion does the number of streams have to the materials 
composing the plain ? Do the streams have many 
tributaries ? What relation does this fact have to the 
sandy character of the plain? Where are the slopes of 
the outwash plain steepest, near the moraine or distant 
from it ? What relation has this fact to the origin of 
the outwash plain ? 

Whitewater Sheet, Wisconsin. — A terminal moraine 
extends across the map northeast from Whitewater 
Lake. Is it, as a whole, higher or lower than the ad- 
jacent country ? How much ? What is its average 
width ? How would you describe the surface of the 
moraine ? Are there depressions ? By what kind of a 
contour line are these depressions indicated? About 
how deep are most of them ? How deep below the 
general level is the pond about three miles southeast 
of Palmyra? Would the description "hillock and hum- 
mock " apply to the surface of the moraine ? Are 
the ponds and depressions such as would be produced 
by the usual processes of erosion ? The ice by which 
the moraine was built lay on the northwestern side. 
Make a profile across the moraine from Palmyra to 
Country Lake. Which slope is steepest, the northwest 
or southeast ? Why should it be steep on the ice side ? 



GLACIATION 157 

What features do you find similar to the moraine on 
Long Island ? 

*119. COMPARISON OF GROUND MORAINE AND 
MARGINAL MORAINE 

Whitewater, Wis., or St. Paul, Minn., Quadrangle and 
Mount Sterling, Ohio, Quadrangle. — Where is a mar- 
ginal moraine built ? A ground moraine ? The Mount 
Sterling region is covered with a ground moraine largely 
composed of till. How does the surface of a ground 
moraine compare with that of a marginal moraine, as to 
smoothness and drainage ? Find, and sketch, types to 
illustrate your answer. Which kind of moraine makes 
the best agricultural land ? Why ? 

120. A COMPARISON OF MOUNTAINS MODIFIED BY MOUN- 
TAIN OR ALPINE GLACIATION AND BY CONTINENTAL 
GLACIATION. 

Mount Marcy Quadrangle, New York, and Gilbert 
Peak Quadrangle, Utah-Wyoming. — The Adirondacks 
were overridden by the continental glacier, while the 
glaciation in Utah was of the Alpine type. What is 
the height of Mount Marcy ? Of Gilbert Peak ? What 
glacial features are common to both regions ? What 
are peculiar to Alpine glaciation? Which type of gla- 
cial erosion produces the smoothest topography ? Which 
topography could you characterize as smoothed? As 
sharpened f Sketch good types of both examples of 
glacial erosion. 



158 MANUAL OF PHYSICAL GEOGRAPHY 

*121. A COMPARISON OF MOUNTAINS AFFECTED BY 
GLACIAL EROSION AND BY SUBAERIAL EROSION 

Mount Marcy, N.Y., Gilbert Peak, Utah-Wyo., Mount 
Mitchell, N.C.-Tenn., Quadrangles. — Compare Mount 
Marcy, Gilbert Peak, Mount Mitchell, and Blue Ridge 
as to dissection. Which have sharp outlines ? Which 
are most dissected? Which mountains have the steepest 
slopes, those due to glacial erosion or those due to sub- 
aerial erosion ? Which type does Mount Mitchell the 
more resemble, Gilbert Peak or Mount Marcy? How 
could you distinguish them? How could you distinguish 
them by their drainage features ? How does a cirque 
differ from the head-water region of a stream due to 
subaerial erosion ? Is Mount Mitchell an isolated peak 
or a part of a range? How do the Black Mountains differ 
from the Uinta Mountains ? How would Mount Marcy 
differ from its present appearance if it were due entirely 
to subaerial erosion instead of partly to glacial erosion ? 
How high is Mount Mitchell? Mount Marcy? Gilbert 
Peak? 

Sketch a good example, not before mentioned, of a 
mountain characterized by subaerial erosion, by Alpine 
glaciation, and by continental glaciation. 

*122. GLACIAL EROSION. FIORDS 

Boothbay Quadrangle, Maine. — In what part of the 
state is this region ? What is the general shape of the 



GLACIATION 159 

islands and peninsulas? Are the divides straight or 
markedly curving ? Are the bodies of water long or 
round ? How do they compare in this respect with the 
Wisconsin maps ? How do Sheepscot and Damariscotta 
rivers compare with Poquoson and Back rivers of the 
Hampton, Va., Quadrangle ? In what respects are they 
similar? In what, different ? How do the valley sec- 
tions and divides compare ? Which have the best de- 
veloped tributaries ? Which, do you think, are the 
product of normal erosion ? Why ? From a map of 
Maine, determine the length of the Sheepscot and Dam- 
ariscotta rivers. Are they longer or shorter than 
Poquoson and Back rivers ? In which region, the 
Booth bay or the Hampton, does the land slope grad- 
ually toward the sea ? 

During the glacial period the ice moved over the 
Boothbay region in a general north-south direction. 
What effect would this movement have on the existing 
river valleys? What effect would it have on the de- 
velopment of tributaries, as compared with the Hampton 
region? Such long, narrow arms of the sea are called 
fiords. How deep is the Sheepscot River below the 
general elevation of the region ? West of Barter Island 
the water is 12J fathoms deep, and west of Southport 
Island the water is about 24 fathoms deep. How deep 
is the bottom of the fiord below the general level ? If 
coast charts Nos. 314 and 315a are at hand, note the 
depths of other fiords. 



160 MANUAL OF PHYSICAL GEOGRAPHY 

Find all contrasts you can between the erosion forms 
of the Hampton, Va., region and the Boothbay region. 
Illustrate by sketches the best types you can find. 

*123. A DIVERTED STREAM (GLACIAL) 

Rochester Special Quadrangle, New York. — How wide 
is the valley of the Genesee River at the southern bor- 
der of the map ? Below Rochester ? What is the alti- 
tude above sea level of the river just north of Genesee 
Junction? At its mouth? How high are the falls in 
the city of Rochester ? {Suggestion : Trace the 500-foot 
contour into the city, and note when it crosses the river, 
and then note the height below the falls.) Are there 
any other falls below the city ? How high are they ? 

Trace on some general map the course of the Genesee 
River. Where does it rise ? Are falls to be expected 
in the upper or lower courses of the river, if they occur 
at all ? Is the stream valley usually wider at the 
mouth or upstream from the mouth ? Explain your 
answer to the preceding two questions, as they may 
be affected by volume and fall of stream. How do your 
answers apply to the Genesee in this region ? 

Compare the tributaries of the river above and below 
Rochester as to number, length, and width. To what 
stage, youthful, mature, or old, does the valley north of 
Rochester belong ? South of Rochester ? The Genesee 
River has been blocked by glacial action and compelled 



GLACIATION 161 

to cut a new channel. About where in this vicinity did 
the blocking occur ? 

Reference. — Tarr's "Physical Geography of New York 
State," pp. 164-167. 

*124. DRUMLINS 

Sun Prairie Sheet, Wisconsin. — In what part of 
Wisconsin? What is the distance and direction from 
Milwaukee ? About how high is the plain on which 
the drumlins stand? Are the drumlins of uniform 
height ? How high is the highest above the adjacent 
country ? The lowest ? What variation in height ? 
How would you describe the ground outline of the 
drumlins ? Make a north-south profile and an east-west 
profile across the drumlin east of Sun Prairie. In 
general, are the north slopes and the south slopes 
equal ? Note the double or " twin drumlins " southwest 
of Cottage Grove. Where are others ? With the pro- 
tractor get the direction of the longer axis of the follow- 
ing drumlins (e.g. the direction of axis of the drumlin 
east of Sun Prairie is north, east 43°) : east of Goose 
Lake, east of Mud Lake, south of London, west of 
Cambridge, south of Nora, southwest of Hope, north 
of Vilas, north of Aclsit, southwest of Sun Prairie, 
northwest of Sun Prairie. What evidences of glacia- 
tion, other than drumlins, do you find in this region ? 






162 MANUAL OF PHYSICAL GEOGRAPHY 

125. COMPARISON OF GLACIAL EROSION AND GLACIAL 
DEPOSITION 

Boothbay, Me., Whitewater, Wis., and Mount Sterling, 
Ohio, Quadrangles. — Which, of these regions represent 
glacial deposition ? Which glacial erosion ? Which 
region has_ a smoothed topography ? Which a smooth 
topography ? Is stream development better in the 
Mount Sterling or the Boothbay region ? How would 
you explain your answer ? Which region has the 
roughest topography? Which region has the highest 
hills ? Which, the deepest valleys ? Which has the 
best drainage ? Which, the poorest ? Which region do 
you think has the best agricultural land ? Which, the 
poorest? Why? Sketch a good example three miles 
square of ice-eroded topography ; of marginal moraine ; 
of a ground moraine. 

126. SAND PLAINS AND ICE-CONTACT SLOPES 

Abington Quadrangle, Massachusetts. — How far, and 
in what direction, is this region from Boston ? Extend- 
ing from Northville is a line of hills curving to the 
southwest, and at East Bridgewater the line curves to 
the northwest. About a mile and a half south is 
another line of hills parallel to this. Do these hills, as 
a rule, have slopes equal in all directions ? In general, 
are their short slopes in the same direction ? Their 
long slopes ? Have any of the hills lobes ? 



GL AC I AT ION 163 

A lobe of ice extended down the valley of the Matfield 
River. (Why should it extend farther south in the 
valley than on the uplands ?) Streams from this ice 
built cones and deltas at the ice margin. Would such a 
form be steepest on the ice-contact side or on the out- 
wash side ? Why ? Would some of them be lobate ? 
Why? Sketch a good example of a hill showing the 
ice-contact slope and the out-wash slope. Sketch a 
good example showing a lobate outline. Draw a map 
showing the successive positions of the ice front as 
shown by the lines of hills. 

127. GENERAL EXERCISE 

Watkins Quadrangle, New York. — This region was 
overridden by the ice of the Wisconsin period. The 
valley in which Seneca Lake is located was scoured. 
How much the valley is due to ice action is yet 
uncertain. Later, while the ice was retreating, 
this valley contained a lake which drained south- 
ward through the present valley of Catharine Creek. 
See the Watkins Glen Quadrangle, and trace the valley 
of Catharine Creek. Does this creek occupy the entire 
valley ? Where are its head waters ? How would you 
describe the divide between Catharine Creek and New- 
town Creek ? Is this a normal divide ? Why ? Com- 
pare it with other divides, e.g. between Bulkley Creek 
and Cayuta Creek. 



164 MANUAL OF PHYSICAL GEOGRAPHY 

What evidence north of North Elmira that the outlet 
of the old Seneca Lake discharged through the valley ? 
What bearing has this on the exercise ? 

Hanging Deltas. — Along the larger creeks as at Wat- 
kins Glen and Hector Falls, you will note that the con- 
tours bow out. What do these forms indicate — a ridge, 
a valley, or level ground ? Is such a feature normal in 
the lower part of the valley? Do the tributaries of 
these creeks have them ? These forms are deltas built 
by the creek when the lake was at higher levels ; 
and when the lake surface was lowered, the streams 
cut through their deltas. How many levels can you 
find ? What do these levels show — a stationary, rising, 
or a lowering surface ? Do these levels correspond in 
elevation on the deltas of different streams ? 

Ice Erosion. — How would you describe the slopes of 
the valley sides of Seneca Lake ? Their dissection ? 
Are the ravines deep ? Compare in this respect with 
the valleys of the Chemung, Elmira, N.Y., Quadrangle, 
and Ohio, Charleston, W. Va., Quadrangle. What rela- 
tion has this smoothness of valley side to ice action ? 

Note Big Hollow Run, north of Watkins. Make 
a profile of the stream. Is this profile a normal 
one ? Give full reasons for your answer. Do most of 
the streams running east or west into the lake have a 
similar profile ? Does Catharine Creek have a similar 
profile ? Wnere have you seen profiles similar to that 



GLAGIATION 165 

of Big Hollow Run ? What is their significance ? 
Why does Catharine Creek not have a similar profile ? 
Deltas. — What kind of topography at the head of 
Seneca Lake Valley ? How was it made ? Is its 
margin stationary, advancing, or retreating ? Explain 
the points of low land along the lake shore opposite 
each creek. 

Reference. — Tarr's " Physical Geography of New York State," 
p. 176. 

128. GENERAL REVIEW 

The following quadrangles mounted together : 
Minneapolis, St. Paid, White Bear, and Anoka (Minn.) 
Quadrangles. (For a class of average size, one or two 
mounted maps will be sufficient.) 

The St. Paul Quadrangle shows a fine example of a 
moraine. What features of topography and drainage 
are characteristic of a moraine ? Are these features as 
prominent in St. Paul as in the surrounding country ? 
Trace the moraine on the mounted map. Where is 
it most marked ? How high is the moraine on the 
average ? How high is the region in the northern part 
of the grouped maps ? What kind of a moraine is it 
here ? What kind in the southern part ? 

Make a cross section of the Mississippi Valley at 
South St. Paul and in Minneapolis. How do they 
compare in all respects ? How do they compare with 
the valley above Minneapolis ? How with the valley 



166 MANUAL OF PHYSICAL GEOGRAPHY 

of the Minnesota River ? Compare the Mississippi 
above Minneapolis; between Minneapolis and Pike 
Island ; below Pike Island and the Minnesota Valley, 
with respect to how they Jit their valleys. Where are 
St. Anthony Falls ? How high ? Do falls or rapids 
remain stationary or do they migrate ? Why ? Which 
way do they migrate, up- or downstream ? 

How high are Minnehaha Falls ? How far have they 
migrated since their origin ? The Mississippi River 
once followed the valley of the Minnesota. The 
preglacial Mississippi was blocked by a moraine and 
compelled to make a new channel, and the river joined 
its old valley at Pike Island. Explain the foregoing 
features in the light of this history. What was the 
origin of St. Anthony Falls ? Where did they begin ? 
Why have they receded farther than Minnehaha Falls ? 
What physiographic feature determined the location of 
each of the " Twin Cities" ? For what manufacture 
are they notable ? What strategic value has Fort Snell- 
ing? 

*129. A COMPARISON OF DRIFTLESS, NEW DRIFT, AND 
OLDER DRIFT AREAS 

Lancaster, Wis., Portage, Wis., and Anamosa, la., 
Quadrangles. — How many square miles in the Lan- 
caster area? How far, and in what direction, is 
Lancaster from Chicago ? What is the average height 



GLACIATION 167 

of the region above sea level ? What average depth 
have the deeper valleys? What is the shape of the 
cross section of the principal valleys ? Of the minor 
valleys ? Have all of them flood plains ? Have any of 
them flood plains ? How wide is the widest flood 
plain ? Do flood plains occur in the upper or lower 
part of the valleys ? Make a profile of Platte River, 
from Annaton to its mouth. What is the rate of 
descent in its upper part ? Its lower part ? What is 
the height of the plateau east of Annaton ? What is 
the slope of the country from there to the mouth of the 
Platte River ? How would you describe the divides, as 
broad or narrow ? Is the run-off good or poor ? 

The quadrangle is a portion of a dissected plateau. 
What remnants of the plateau ? Where ? What is 
their general height ? What proportion of the original 
plateau surface, would you estimate, remains? 

Portage, Wis., Quadrangle. — How far, and in what 
direction, from Lancaster is Portage ? In what part of 
Wisconsin is Portage ? How far, and in what direction, 
from Milwaukee ? How do the valleys compare in 
cross section with those of the Lancaster map ? How 
deep are the valleys ? How does this depth compare 
with that of the valleys in the Lancaster region ? Which 
way does the Fox River flow ? Can you determine by 
the contours? What is the length of the Fox River? 
About what is the fall per mile in this region ? How 



168 MANUAL OF PHYSICAL GEOGRAPHY 

does this compare with that of the rivers in the Lancas- 
ter region ? What do you notice about the width of 
Fox River Valley ? Is it uniformly wide ? Does it 
widen downstream? Do most stream valleys widen 
downstream ? How would you describe the divides ? 
How do they compare with those of the Lancaster 
region? How do you describe the run-off? Which 
would be more subject to floods, the rainfall being 
equal, the Fox or the Platte River ? How much of the 
area, do you estimate, is in swamp ? How much is 
covered by lakes ? How does the number of tributa- 
ries in this region compare with that of the Lancaster 
region ? Where are most of the roads in the Portage 
region ? Where does the Fox River lead ? The Wis- 
consin ? How are they connected ? How high is the 
divide between them ? This was an old canoe portage 
before the canal was dug, hence the name of the city. 
This region is overlaid with drift of late Wisconsin a^e. 
Anamosa Quadrangle, Iowa. — How is this quad- 
rangle located with respect to the Lancaster Quad- 
rangle ? W 7 ould you describe the divides as broad 
or narrow ? Are they distinct or indistinct ? High 
or low ? How do they compare in these respects 
with the Lancaster and Portage areas ? Is the run-off 
good or poor ? Is the region well drained ? How does 
the number of tributaries compare with that of the other 
areas ? Are the valley sides steep ? Do they vary in 



GLACIATION 169 

this respect ? Do the valleys vary in width ? Most of 
these variations are due to deflection by ice work. For 
example, does the Maquoketa below Monticello follow 
a usual behavior ? The river is believed to have flowed 
through the Scotch Grove region, southeast of Monti- 
cello. Does a map study corroborate this belief ? 
This region is overlaid by drift older than that of the 
Portage region. 

Resume. — In the Lancaster county we have a region 
not glaciated ; in the Portage region the country is over- 
laid by young drift of the last glacial period ; in the 
Anamosa region the country is overlaid by drift older 
than that of the Portage region (probably of Iowan 
age). We have a good opportunity to compare a topog- 
raphy developed by subaerial erosion, one by recent 
glaciation, and one by older glaciation and subsequent 
stream work. Compare carefully their dissection (stage, 
shapes of valleys, uplands, divides), their stream pro- 
files, tributaries, run-off, and completeness of drainage. 
Draw type examples from each locality. 

Glaciated and Uhglaciated Regions. Raritan Quad- 
rangle, Neiv Jersey. — From the drainage conditions, 
determine approximately the glaciated and the un- 
glaciated portions of this quadrangle. 

Give reasons for your answers. 



CHAPTER XIII 

LAKES 
*130. OXBOW LAKE 

Elk Point Quadrangle, South Dakota -Nebraska— Ioiva. 
— To what class does McCook Lake belong? What 
other example ? Has it an inlet ? An outlet ? Why 
does it not dry up ? What is the origin of this class 
of lakes ? Where are others likely to be formed ? 

*131. LAKES AND SWAMPS ON A FLOOD PLAIN 

Marysville Quadrangle, California. — Review Exer- 
cise 57- What do the swamps and lakes on either side 
of the Sacramento River indicate, high or low land ? 
Give reasons for your answer. What is the origin of 
Butte Slough and Long Lake ? Do you think these 
lakes are deep or shallow? 

132. DELTA LAKES 

East Delta Quadrangle, Louisiana. — Review Exer- 
cise 59. Which do you think first existed, Jackass 
Bay or the passes north and south of the lake ? Was 
the lake formerly larger or smaller than at present ? 
Is it likely to increase or decrease in area? Why? 

170 



LAKES 171 

What is the origin of the lake ? May Blind Bay ever 
become a lake ? If so, how ? 

133. LAKES IN ROCK BASINS 

Gilbert Peak Quadrangle, Utah - Wyoming. — Review 
Exercise 116. Are cirques due primarily to ice erosion 
or ice deposition ? Would you expect the bottoms of 
cirques to be of drift or of solid rock ? What is the 
origin of most of the lakes, such as Fish Lake ? 

•134. AN ICE-BLOCKED VALLEY 

Mount Marcy Quadrangle, New York. — What is the 
general elevation of the upland ? How far beneath this 
elevation are the upper and lower Ausable Lakes ? 
How wide is the valley of lower Ausable Lake ? How 
wide is the lake ? This valley is thought to be a pre- 
glacial valley, subsequently eroded by ice and later 
blocked by drift. How does the valley resemble a 
normal erosion valley ? An ice-eroded valley ? 

*135. MORAINIC LAKES 

Whitewater Quadrangle, Wisconsin. — Review Exer- 
cise 118. What is the principal agent that has 
fashioned the topography of this region ? Trace the 
principal moraine. How many lakes are there on 
the moraine ? Are there any depressions that do not 
contain water ? Are there any depressions that are only 



172 MANUAL OF PHYSICAL GEOGRAPHY 

partly filled? Do most of these morainal lakes have 
inlets ? Outlets ? How do they get their water ? What 
becomes of their water ? Roundish morainic lakes in a 
moraine are called " kettle lakes." Are the lakes near 
Palmyra and Whitewater kettle lakes ? 

136. AN EXTINCT MARGINAL GLACIAL LAKE 

Passaic, N.J.—N.Y., and Raritan, N.J., Quadrangles. 
— Beginning at Paterson, note the valley of the Passaic 
River. How wide is the valley ? Where does the Pas- 
saic head ? Where does it empty ? Does it take a 
direct course to its outlet ? Are the swamps in its 
upper or lower course ? Is this the normal location 
of swamps ? Where does the basin, in which the val- 
ley lies, end ? What are the boundaries of this valley? 
How high are the Watchung ridges? Where are there 
notches in these ridges? How low are these notches 
below the crests of the ridges? 

In the preglacial times the Passaic is thought to 
have crossed the ridges near Short Hills. During the 
glacial period the ice occupied the Passaic basin. When 
the ice front had retreated northeast of the Second 
Watchung, a marginal lake was formed. Why ? Where 
would be its main outlet ? Into what river would this 
outlet flow ? At this time, how deep was the water at 
Liberty Corner (about seven miles north of Somerville) ? 

When the ice margin reached the vicinity of Madison 



LAKES 173 

and Chatham, it halted and built a moraine. Trace this 
moraine. What morainal characteristics has it ? What 
effect would it have on the Short Hills outlet ? From 
here the ice front retreated until the gap at Paterson 
was passed. What effect would this exposure of the 
gap have on Lake Passaic? 

After the water of Lake Passaic had mostly disap- 
peared, the depressions in the lake bed were still filled 
with water (consequent lakes). Great Piece Meadows 
and Great Swamp are sites of two of these lakes. Why 
should these sites still be swamps ? Make a sketch 
showing the borders of Lake Passaic, the first outlet 
near Far Hills (eight miles north of Somerville), the 
moraine built during the ice retreat, and the final outlet 
at Paterson. 

What effects have these swamps on the life of the 
inhabitants ? Where are the swamps being drained ? 
What uses are made of the moraine near Short Hills? 
Why is there a falls at Paterson ? What geographic 
factors in the location of Paterson ? 

Reference. — An excellent account of Lake Passaic is given 
by Professor E. D. Salisbury in Chap. 5, Vol. 5, " Glacial Geol- 
ogy of New Jersey," Final Report, 1902. 

137. A CRATER LAKE 

Crater Lake Special, Oregon. — In what part of 
Oregon is Crater Lake ? Of what range of mountains 



174 MANUAL OF PHYSICAL GEOGRAPHY 

is it a part ? What is the average diameter of the lake? 
How high is the water surface above sea level? What 
is the average depth of the water surface below the 
surrounding cliffs ? What is the average depth of the 
lake? 

Make a profile from the Watchman west to the 
margin of the map and from Sentinel Rock east to 
the base of Scott's Peak. How do the outer slopes of 
Mount Mazama compare with the slopes toward the 
lake ? Continue your profiles until they meet. Their 
intersection represents roughly the former height of 
the mountain. How high above the present Mount 
Mazama is this intersection ? How do the slopes of 
the lake bottom off the Palisades (northeast shore) 
compare with the southwestern slopes of the Palisades ? 

Read the description on the back of the map. What 
is the probable origin of Crater Lake ? What signifi- 
cance with this origin have (a) the outer and the inner 
slopes of Mount Mazama, (b) the slopes of the lake 
bottom, (c) the inlets and outlets, if any, of Crater 
Lake ? What significance in the radial arrangement 
of the valleys on the mountain side and their upper 
termination ? 

Compare this lake in the above-named features with 
the lakes previously studied. Which types of lakes 
does it most resemble? 

Compare Mount Mazama with Mount Shasta as to 



LAKES 175 

lava-flows, coulees, dissection, and slopes. Compare it 
with Marysville Buttes as to dissection. 

138. CONSEQUENT AND SOLUTION LAKES 

Arredono Quadrangle, Florida. — How does this sur- 
face compare with a glaciated surface, e.g. the White- 
water, Wis., region ? In what stage of erosion is the 
region ? About what percentage of the surface is cov- 
ered with water? Do you think the lakes are shallow 
or deep? Do they have outlets? Inlets? Are the 
lakes variable in area ? How far above sea level are 
most of them ? 

The surface of Florida is youthful geologically and 
largely underlaid by very soluble rocks. The lakes 
are probably in part consequent, and in part due to 
solution. 

139. LAKES DUE TO FAULTING 

Alturas, Cat., and Long Valley, Nev., Quadrangles. — 
Review Exercise 106. What is the origin of Upper 
Lake, Middle Alkali Lake, and Lower Lake? Why 
are they nearly in a straight line ? Do they have an 
outlet ? Why ? Why are their waters alkaline ? 

Find lakes of similar origin on the Long Valley 
Quadrangle. Do these lakes appear to have .a constant 
volume? Give reasons for your answer. 



176 MANUAL OF PHYSICAL GEOGRAPHY 

140. A NEARLY DRAINED LAKE 

Sierraville Quadrangle, California. — Sierra Valley 
was once occupied by a lake. What is the area of this 
valley ? What was the outlet of the lake ? By what 
two agencies was the former lake drained ? How deep 
is the Feather River Valley below the general level of 
the upland ? Which part of the lake bed is best 
drained? What topographic forms were the "buttes" 
when a lake occupied the valley ? Do you think that 
the former lake shore was smooth or indented ? Why 
is the present bottom of the Sierra Valley smoother 
than the uplands ? Which would make the best agri- 
cultural lands ? (Give several reasons.) 

*141. LAKES AS FILTERS 

Charts of Lake Ontario and Lake Erie. — Which 
river, the Niagara or the Maumee, do you think has the 
greatest volume ? Why ? How large an area has the 
delta at the western end of Lake Erie? Is there a 
similar delta at the mouth of the Niagara ? Is the 
volume of the Niagara River about equal to the combined 
volumes of the streams entering the western end of 
Lake Erie ? How would you explain the contrast in 
their deltas ? 



CHAPTER XIV 

THE OCEAN 

142. DEPTHS OF THE ATLANTIC ALONG THE PARAL- 
LEL OF 40°, FROM NORTH AMERICA TO EUROPE 



U. S. 15 miles 


19 fathoms 


2100 miles 


1130 fathoms 


125 miles 


40 fathoms 


2150 miles 


609 fathoms 


250 miles 


1460 fathoms 


2250 miles 


1200 fathoms 


500 miles 


2800 fathoms 


2500 miles 


2360 fathoms 


1000 miles 


2930 fathoms 


2750 miles 


2650 fathoms 


1500 miles 


2675 fathoms 


3125 miles 


2090 fathoms 


1750 miles 


2600 fathoms 


3190 miles 


60 fathoms 


2050 miles 


1230 fathoms 


3230 miles 


Land (Europe) 



Make a profile of the bed of the Atlantic. Allow 
one inch to represent 100 miles and a small square to 
represent 100 fathoms. Leave margins at the sides of 
the sheet so the sheets may be pasted together. 

What State does the parallel of 40° touch ? What 
country in Europe ? Which part of the profile shows 
the least relief of the ocean bed ? Where is the greatest 
depth in the profile along the fortieth parallel ? How 
many miles is it from America ? From Europe ? Locate 
the platform on which are the Azores. About how far 
from both coasts are the continental slopes ? Which 

n 177 



178 MANUAL OF PHYSICAL GEOGRAPHY 

continent has the wider shelf ? What is approximately 
the average depth of the Atlantic along the parallel 
of 40° ? 

*143. THE CONTINENTAL SHELF 

Coast Chart No. 1007, The Gulf of Mexico and 
Sti^aits of Florida. — What is the scale of this map ? 
Make a generalized profile along the line of soundings 
north of Cape Canaveral from the coast to the eastern 
edge of the map. (Use 100-fathom contour interval.) 
Where is the steepest slope ? What is the average slope 
per mile here ? Where is the edge of the continental 
shelf? What is the average slope of the continental 
shelf from the coast to its edge ? From the edge of the 
continental shelf to its base? 

Coast Chart No. 5300, Santa Rosa Island to Point 
Buchon, Cat. — In what part of California is this 
region ? Make a profile along the line of soundings in 
the middle of the chart. Compare it with the profile 
of the continental shelf of the Atlantic coast. 

*H4. DAILY TIDES 

Plot the tidal curve for Boston. Along the longer 
edge of the paper, number each small square for each 
hour, beginning at midnight. Along the shorter edge, 
allow each large square to represent one foot. Write the 
dates of the month above the squares in their appro- 



THE OCEAN 



179 



priate places. The minus numbers indicate tides below 
the mean sea level. 

Tide Table for January 1 to 4, 1909. Boston, Mass. 



Jan. 1 


6.45 a.m. 


9.7 


Jan. 3 


2.27 a.m. 


0.3 




1.10 P.M. 


0.1 




8.40 a.m. 


10.1 




7.20 p.m. 


8.9 




3.08 p.m. 
9.21 p.m. 


-0.3 

8.8 


Jan. 2 


1.30 A.M. 


0.3 










7.44 a.m. 


9.9 


Jan. 4 


3.20 a.m. 


0.3 




2.11 P.M. 


-0.1 




9.32 a.m. 


10.3 




8.22 p.m. 


8.8 




4.00 p.m. 
10.13 p.m. 


-0.5 

8.8 



Are the high tides of the same height ? Are the low 
tides ? What is the average tidal range ? How many 
high tides, in the average, in each day ? How many 
low tides ? Do the high and low tides occur at a corre- 
sponding hour each day ? What is the average differ- 
ence in time between high tides for the above dates ? 
Between low tides ? How much later, on the average, 
does the tide rise each succeeding day? Why is it 
that the hour for sea bathing at many resorts changes 
from day to day ? Why do ships often leave or enter 
harbor late at night ? 

*145. DAILY HIGH TIDES 

Plot the curve of highest tides. When are the tides 
highest ? When lowest ? How many maxima in a 
month ? How many minima? 



180 



MANUAL OF PHYSICAL GEOGRAPHY 



Table giving the Highest Tides on Each Day at Sandy 
Hook, N.J., January 1 to January 31, 1909 



Jan. 1 


4.8 


Jan. 9 


4.8 


Jan. 17 


4.5 


Jan. 25 


5.3 


2 


4.9 


10 


4.5 


18 


4.8 


26 


5.0 


3 


5.1 


11 


4.3 


19 


5.1 


27 


4.7 


4 


5.2 


12 


4.0 


20 


5.3 


28 


4.8 


5 


5.3 


13 


4.0 


21 


5.5 


29 


4.8 


6 


5.3 


14 


4.0 


22 


5.7 


30 


4.7 


7 


5.2 


15 


4.1 


23 


5.6 


31 


4.7 


8 


5.0 


16 


4.2 


24 


5.5 







The moon is full January 6, and new January 21. 
The third quarter comes January 14, and the first 
quarter January 28. Place the following symbols 
above your curve : for the new moon % ; the full 
moon O ) the first quarter ]) ; the third quarter ([ . 

With what phases of the moon do the maxima and 
minima of the tides approximately coincide ? Draw 
diagrams showing the positions of the earth and moon 
at each phase. Explain your curve. Label your tidal 
curve at the proper places "spring tides" and "neap 
tides." 



146. TIDES ON A SMOOTH AND AN INDENTED COAST 

Locate Bath and Sandy Hook (Bath, Me., and 
Navesink, N.J., Quadrangles). How do the coasts 
compare in smoothness ? 

Plot the tides for Bath and Sandy Hook. (Use the 



THE OCEAN 



181 



same method as in Exercise 144.) Which place has 
the highest tides ? Explain the differences in view 
of the different coast lines. 



Bath, Me. 


Tide 


Sakdy 


Hook, N.J. 


Tide 


Jan. 1 


12.01 A.M. 


0.7 


Jan. 1 


3.08 A.M. 


4.8 




6.19 A.M. 


6.3 




9.34 a.m. 


0.3 




12.41 p.m. 


-0.7 




3.40 p.m. 


4.2 




6.56 p.m. 


6.0 




9.44 p.m. 


0.0 


Jan. 2 


12.02 a.m. 


0.2 


Jan. 2 


4.05 a.m. 


4.9 




7.17 A.M. 


6.5 




10.35 a.m. 


0.2 




1.44 p.m. 


-0.2 




4.40 p.m. 


4.2 




8.00 p.m. 


5.9 




10.40 p.m. 


0.0 



Compare the times of high and low tides at the two 
places. 

147. LAGGING OF THE TIDES 

The Average Time of High Water after the Moon's 
Transit is given in the Following Table 



Honolulu 6 hr. 48 min. 

Apia (Samoan Is.) 6 hr. 25 min. 

St. Helena 3 hr. 00 min. 

Canary Is 1 hr. 15 min. 

Liverpool 10 hr. 56 min. 

Bath, Me 12 hr. 13 min. 

Boston, Mass 11 hr. 28 min. 



Locate all of these places on a map or globe. Which 
are continental ? Which insular ? Which ports have 
the greatest lagging ? Explain your answer. 



182 



MANUAL OF PHYSICAL GEOGRAPHY 



148. TIDAL CURRENTS 

Tide Tables fob January 1 at Willets Point and 
Governors Island 



Willets Point 


Tide 


Governors Island 


Tide 


12.25 a.m. 
6.36 a m. 
1.30 p m. 
7.15 p m. 


0.3 

7.5 
02 
6.7 


3.40 a m. 

10.15 AM. 

4.00 p.m. 
10.22 p m. 


4.5 

0.1 

4.0 

-0.2 



Locate Willets Point, Governors Island, and Sandy 
Hook on Chart No. 120, New York Bay and Harbor. 
Plot the tidal curves for these places. What is the 
body of water connecting these places ? How long is 
it? Wliat is the tidal phase at the two places 12.25 
a.m.? At 6.36 a.m.? At 1.30 p.m.? At 7.15 p.m.? 
Which way will the tidal currents move at each of these 
times ? From your curve determine what relations of 
tidal phases about 11 a.m. and 3 p.m. 

What configuration of the coast favors these currents ? 
What effect have they on the channel ? Why is Hell 
Gate somewhat dangerous for navigation ? 



*149. OCEANIC AND COASTAL TIDES 

Plot on the same sheet the curves for Honolulu and 
San Francisco. (Use half squares on the longer lines 
for hours, and the small squares on the shorter lines for 



THE OCEAN 



183 



tenths of a foot.) What is the greatest range for each 
place? What is the average range for each place? 

Honolulu and San Francisco 



Honolulu 


Tide 


San Francisco 


Tide 


Jan. 


1 


12.22 p.m. 


1.5 


Jan. 1 


12.28 a.m. 


1.9 






7.07 a.m. 


0.4 




7.10 A.M. 


5.8 






11.45 A.M. 


0.8 




1.56 p.m. 


0.7 






5.37 a.m. 


-0.1 




8.45 p.m. 


4.2 


Jan. 


2 


1.07 A.M. 


1.8 


Jan. 2 


1.22 A.M. 


2.4 






8.17 A.M. 


0.3 




7.52 a.m. 


6.0 






12.46 p.m. 


0.7 




2.52 p.m. 


0.0 






6.22 p.m. 


-0.1 




9.52 p.m. 


4.3 



Locate the two cities on a globe. Explain the differ- 
ence in their ranges. 

*150. OCEAN CURRENTS 

From a good map, make a sketch map of the princi- 
pal ocean currents, noting their positions, directions, 
and widths. 

From pilot charts of the North Atlantic Ocean and 
the North Pacific Ocean, sketch the currents shown. 

The Gulf Stream 

Coast Chart No. 1007, Gulf of Mexico — See "Gulf 
Stream Currents." Is the velocity constant or variable? 
What is the average velocity in the Yucatan Channel ? 
South of Rebecca Shoal ? East of Cape Florida ? 



184 MANUAL OF PHYSICAL GEOGRAPHY 

151. AN ATOLL 

Funafuti Atoll. Chart iVb. 1802, Hydrographic 
Office. — What is the scale of this niap ? What is the 
average depth of water two miles from the land ? One 
mile ? Is the slope from land to sea bottom steep ? 
How does it compare in steepness with the steep part 
of the continental shelf (Exercise 143)? With the coast 
of New Jersey (see Chart No. 121) ? So far as it is 
shown, by what is the sea bottom covered ? 

About how long is the rim of land ? About what 
average width ? Is it continuous ? About how high is 
the rim ? Is it, as a rule, bare or wooded ? Of what do 
you think it is composed ? How is it built up so high 
above sea level? What causes the openings in the 
rim ? What openings are suitable for vessels ? 

What would you say is the average depth of water 
wuthin the rim ? Is the bottom level ? Is it more or 
less level than the sea bottoms you have previously 
studied ? Is the slope from the reef within greater or 
less than from the reef seaward ? 

About how high above the general level of the sea 
bottom is the bottom within the atoll ? Do you think 
there is much animal life on the land ? Of what is the 
sea bottom within the atoll mainly composed ? What 
is the latitude and longitude of Funafuti Island ? 
What direction from San Francisco ? About how far ? 



THE OCEAN 185 

*152. CORAL REEFS 

Coast Charts No. 1007, Gulf of Mexico ; No. 169, 
Newfoundland Harbor Key to Boca Grande Key. — On 
the large chart, you will note the line of coral- 
built structures extending from Florida westward. 
How long is this line of reefs and keys ? About how 
wide ? What similar formations along the coast of 
Cuba ? Along Great Bahama Island ? From how 
deep water do they rise along the straits of Florida ? 
Do they rise suddenly or gradually ? Do the Florida 
reefs continue northward beyond the Gulf Stream? 
What reasons can you give ? (Shaler states that the 
reefs begin at about 27° north latitude.) 

Chart No. 169 shows a portion of the reefs. What 
portion ? What are the parts of the reefs above water 
called ? How would you account for the bodies of 
water in the keys west of Key West ? Why is the sea 
bottom mostly covered with white sand ? 

Chart of the Hydrographic Office, No. 1850, Harbor 
of Apra, Island of Guam. What part of the reef north 
of the harbor is above water ? How long is the Lumi- 
nan Reef and its extension, Calalan Bank ? How wide 
is the 6-foot reef on the south side of the harbor ? 
(See explanation in the lower left-hand corner of the 
chart.) How wide is the 18-foot reef here ? Is the 
shore behind the reef steep or shelving ? How high is 



186 MANUAL OF PHYSICAL GEOGRAPHY 

the Orote Peninsula? Does any of the reef here 
support a tree growth? How wide is the entrance to 
the harbor ? What reasons can you give why this 
opening does not become filled by coral growth ? How 
deep is the opening ? What formation between Orote 
Island and the mainland ? Has the main reef here as 
many openings as the Florida reef ? As many keys ? 
For a study of the harbor, see Exercise 170. 



CHAPTER XV 

SHORE LINES AND FORMS 

*153. COMPARISON OF SUBAERIAL AND SUBMARINE 
TOPOGRAPHY 

Study one or more of the following series of coast 
survey charts and the quadrangles showing the adjacent 
land. What department issues the charts ? The topo- 
graphic maps ? How are altitudes indicated in each 
map ? In each case, determine the following points : 
What is the scale of each map and chart ? How many 
miles does an inch represent in each ? Which area, the 
land or the submarine, shows the greatest contrasts in 
elevations ? In slopes ? In dissection ? 

Tamalpais Quadrangle, California. Coast Chart of 
San Francisco Entrance, No. 5532. — Note, on the chart, 
the Four Fathom Bank west of Point Bonita. Using 
a contour interval of 25 feet, sketch an area of 9 square 
miles on the Four Fathom Bank and an equal area 
on the land to the east. Compare your sketches. 

Navesink Quadrangle, New Jersey-New York. Coast 
Chart No. 121, Sandy Hook to Bamegat Inlet. — Note 
the fathom contour on the chart east of Seagirt. How 
deep is the water here ? Using a 20-foot contour inter- 

187 



188 MANUAL OF PHYSICAL GEOGRAPHY 

val, sketch an area three miles square here, and an 
equal area on the land to the westward. Compare your 
sketches. 

Provincetown and Wellfieet Quadrangles, Massachu- 
setts. Coast Chart No. 110, Cape Cod Bay. — Make 
sketches about four miles square, using a contour inter- 
val of 20 feet, of the following areas : The township of 
Truro (Provincetown quadrangle) and the sea bottom 
immediately adjacent on the east, or a portion of the 
same township in the northern part of the Wellfieet 
Quadrangle with the sea bottom on the east. 

154. A YOUNG COAST 

*Part I. Boothbay Quadrangle, Maine. — How far, 
and in what direction, is this region from Portland? 
From Boston ? How Ions; would the coast line be if it 
extended in a straight line from Pemaquid Point to 
Griffith Head ? How long is the coast line ? (Let 
members of the class measure the following portions of 
the coast line according; to the method in Exercise 65 : 
Pemaquid Point to Crow Island; Crow Island to Peter 
Island ; Carlisle Point to Ocean Point ; Ocean Point to 
Spruce Point ; Spruce Point to Cape Newagen ; Cape 
Newagen to Quarry Point; Quarry Point to Griffith 
Head.) 

Do you think the coast has been much eroded ? Do 
you find bars or spits? What explanation would you 



SHORE LINES AND FORMS 189 

give to your answer ? Does this mean that it is older 
or younger in age? Will the coast become smoother or 
more indented as erosion continues ? 

Part II. Neiv London Quadrangle, Connecticut. Coast 
Chart of the Thames River and the Haroor of New 
London, No. 359. — Was this coast at first as much in- 
dented as the Maine coast? Has it been the more or the 
less smoothed than the Boothbay coast ? What does 
the truncated appearance of Bluff Point and Black Point 
suggest ? What bearing on this question have the 
spits on the western sides of these points ? How deep is 
the water back of Bushy Point Beach ? Do you think 
that the marsh is being filled by the river or by the 
sea ? What bearing on your answer have the numerous 
lakes along Poquonoc River? Do the spits have any 
general direction from their origin ? What explana- 
tion ? How can you account for the ponds north of 
Groton Long Point ? 

Is this coast at an earlier or a later stage than the 

Boothbay coast ? Does this mean that it is older or 

younger in age ? Sketch good types to illustrate your 

answers. 

*155. OFF-SHORE BARS 

Atlantic City Quadrangle, New Jersey. — How far, 
and in what direction, is this region from New York ? 
From Philadelphia? About how far is it from the beach 
to the mainland ? How wide is Brigantine Beach ? 



190 MANUAL OF PHYSICAL GEOGBAPHY 

Island Beach ? How high are these beaches above sea 
level ? Are they connected with the mainland ? Other 
things being equal, as time goes on, are they the more 
or the less likely to be connected with the mainland ? 
Are Brigantine Beach and Island Beach bars or spits ? 
What is the distinction between bars and spits ? What 
do you think the small mounds on the beaches are'? 
Which is the smoother shore of the beaches, the outer 
or the inner? Explain your answer. Are the bars 
continuous or broken? Why are they so? Which way 
do the " hooks " at the ends of the bars generally point ? 
How wide is the area of marshy land (the lagoon) ? 
About what proportion of it is marsh, and what water ? 
Do you think that the marsh was formed before or 
after the bars ? Why ? If the bars were removed, 
would the marsh land be affected ? What part of the 
lagoon is drained artificially ? How has the lagoon 
probably been filled ? How high is the mainland on 
the average ? Does it slope to the shore gently or 
abruptly? What is the slope per mile from Center- 
ville to the marsh ? Make a profile from Smithville 
through Leeds Point to the marsh. On this profile, 
what is the slope of the mainland to the cliff ? What 
is the slope of the cliff ? 

Would you describe the meeting of the land and 
marsh as straight or crooked ? How far northwest or 
southeast from a straight line would this line of meet- 



SHORE LINES AND FORMS 191 

ing swerve ? How does it compare with the meeting 
of land and water on the Boothbay, Me., and the Temal- 
pais, Cal., quadrangles? How does it compare with the 
inner and outer shore of Brigantine Beach ? What 
agency could have cut the cliff and smoothed the shore 
here ? 

Which was first made, and in what order, the bar, 
the lagoon, or the cliff on the mainland ? How many 
railroads lead to Atlantic City. Does the bar offer 
facilities for commerce ? For manufactories ? Account 
for the growth of Atlantic City. What means of com- 
munication are there between the bars and the main- 
land? If Coast Chart No. 123, Absecon Inlet to Cape 
May, is at hand, note the following points : Is the ocean 
bottom off Atlantic City steep or shelving? What is 
its slope per mile for the first mile ? For the first six 
miles ? What relation has this fact to the formation of 
bars ? How deep is the lagoon south of Atlantic City ? 
Is Egg Harbor Inlet larger or smaller than the average 
inlet? How would you explain your answer ? Is this 
coast in an older or a younger stage than that of the 
Boothbay, Me. ; coast ? 

156. SEA CLIFFS AND WING SPITS 

Navesink Quadrangle, JSfeiv Jersey-Hew York. 
Coast Cliart No. 121, Sandy Hook to Barnegat Inlet. — 
What are the scales of the two maps ? How long is 



192 MANUAL OF PHYSICAL GEOGBAPHY 

Sandy Hook from Hook Beacon to Highland Beach? 
How long is it, in inches, on each map ? Is the coast, as 
a whole, smooth or rugged ? High or low ? Where is 
the sea cutting ? Where is its building ? Where are 
there cliffs ? How high are they ? Where are there 
spits ? How high are they ? How broad ? How high 
is the cliff from Long Branch to Point Pleasant ? How 
long? Is the sea cutting or building this cliff? In 
general, is the detritus from this cliff deposited 
eastward from the cliff by the undertow (see the coast 
survey chart) ? How do you know ? If the detritus is 
not carried eastward from the cliff, where must it be 
carried ? Is it carried by currents normal to the shore 
or longitudinal with the shore ? What wind direction 
would produce shore currents flowing northward? 
Southward? How do these facts explain the cliff with 
its attached spits on the north and south ? (Such a 
cliff with its attached spits has been called a cliff with 
wing spits.) Do you think that the coast from Long 
Branch to Point Pleasant has always been so even? 
If the bars before Metedeconk Neck and the unnamed 
peninsula to the north were removed so that the 
waves could attack them, would the coast line be the 
more or the less straightened ? Would it the more or 
the less resemble the Long Branch stretch of coast ? 

Does the spit beginning at Bayhead continue 
southward unbroken ? Why ? Where are the inlets, 



SHORE LINES AND FORMS 193 

in general, located ? How long is the spit which ends 
in Sandy Hook ? Why is it so narrow opposite 
Shrewsbury and Navesink rivers ? Why does this spit 
turn and become a " hook " at its northern part ? 
What strategic value has Sandy Hook ? How is it 
utilized ? 

Would you describe the shore line back of the spits 
as smooth or indented ? Does it indicate a stationary, 
risen, or sunken coast ? Why ? Which is the older, in 
years, the indented shore line back of the spits, or the 
spits? What evidence on the Highlands of Navesink and 
Rumson Neck of former wave action ? As the cliff 
coast is cut back by the waves, will the wing spits on 
either side remain stationary, advance, or retreat? 
Why ? What is the average depth of the dotted area 
east of the coast (from the chart) ? The average 
width ? Is there a similar zone in the Atlantic City 
region ? Is it as uniform in width and as smooth ? 
Is the slope between the dotted area and the undotted 
area gentle or abrupt ? How would you account for 
this abrupt slope ? 

How far ajDart are the life-saving stations ? Why 
are so many necessary ? Are the light-houses uniformly 
grouped along the coast? Why? How high are 
the Navesink lights ? How far are they visible in 
clear weather ? The Hudson formerly had its mouth 
far to the eastward. How is its old channel indicated 



194 MANUAL OF PHYSICAL GEOGRAPHY 

by the 30-fathom curve ? What coastal movement is 
indicated by this fact ? Why does the 30-fathom 
curve disappear near land ? You have on these maps 
examples of a shelving coast, a drowned coast, a cliff 
coast with wing spits derived from it, spits, hook, 
lagoon. Sketch an example of each. 

Reference. — This class of shore lines is described by Tarr, 
"Physical Geography of New York," Chapter X. 

157. TIED ISLANDS 

Boston Bay Quadrangle, Massachusetts. Coast Chart 
of Boston Harbor, No. 337. — Nahant and Little 
Nahant are composed largely of hard, crystalline rock. 
How are they connected to the land ? How high 
are Nahant, Little Nahant, and Lynn Beach ? Which 
have the more rugsred outlines ? Which outlines 
suggest constructive work by the sea and which 
destructive work ? W T hat bearing on this question 
have the altitudes of the localities ? How long is 
Lynn Beach ? How wide ? Is Lynn Beach a narrow 
ridge with steep side slopes, or is it a small area above 
water of much wider spit (see the chart) ? Which of 
these features, the Nahants or Lynn Beach, suggest 
wave work ? Which work by currents ? How ? 
What do you think Lynn Beach is made of ? Why ? 
Find several other good examples of tied islands, and 
sketch the best example. Where are there cliffs on 



SHORE LINES AND FORMS 195 

Deer Island, Long Island, Brewster Islands, Great Hill, 
Sagamore Head? What do you think made the cliffs ? 
Do they for the most part face the same direction ? 
What does this fact suggest, and how would you 
explain it ? From the chart, would you think that 
there are more spits and bars in Boston Harbor than 
the quadrangle shows ? Why is dredging in the 
approaches to Boston necessary ? Are there any 
strong rivers entering Boston Harbor ? 

Problem : Nantasket Beach. 

Great Hill, Strawberry Hill, and Sagamore Head are 
drumlins. Are all their slopes equal ? Why do their 
cliffs face the same direction ? 

What agent is making the cliff at Great Hill and 
Surfside? Do you think the same agent made the 
cliff on Strawberry Hill and White Head ? Are 
the waves now eroding Strawberry Hill ? How far 
from the water is the wave-cut cliff on Strawberry 
Hill now ? Why are the waves not cutting Strawberry 
Hill now? What possible sources for the material 
which has been deposited in front of Strawberry Hill ? 

158. SHORE LINES OF EXTINCT LAKES 

Berea Quadrangle, Ohio. — Taking the region as a 
whole, is there a high area and a lower area ? What 
general altitude has the higher area ? The lower area ? 
Are the areas separated by an escarpment ? Is it steep ? 



196 MANUAL OF PHYSICAL GEOGRAPHY 

What is its average slope per mile ? How does it com- 
pare with the Niagara escarpment ? 

The lower region was covered by the waters of sev- 
eral glacial lakes, among them Lakes Maumee, Whit- 
tlesey, and Warren, which stood at different levels and 
made beaches at those levels. How high was the water 
when Butternut Ridge was made ? Chestnut Ridge ? 
Middle Ridge ? North Ridge ? Draw a profile from 
Olmsted Falls to West Dover. Do the ridges have 
equal slopes on each side ? Is there a plain back of 
each ridge ? In general, are the ridges small escarp- 
ments ? Do you think that they were caused by wave 
cutting or by wave building ? Why ? How much, in 
each case, did the water surface fall before cutting a 
new beach ? Do you think the water surface fell uni- 
formly ? Why ? What do you think was the reason 
that the water surface would fall rapidly and then be- 
come fairly stationary ? 

What is the general trend of the ridges ? Are they 
parallel ? What influence have they on roads ? Why ? 
What kind of soil would you expect them to have, clay, 
sand, or gravel ? Do you think that the valley of Rocky 
River was cut before or after the formation of these 
ridges ? Why ? 

Which is the more dissected, the lake plain or the 
plateau (Alleghany Plateau)? How would the greater 
altitude of the plateau come in as a factor in your 



SHORE LINES AND FORMS 197 

answer ? The duration of exposure ? The hardness of 
materials? At present, what are the waves of Lake 
Erie doing, cutting or building? How high are the 
cliffs along the lake ? Are they much dissected ? What 
is the altitude of Lake Erie? 

Reference. — " Drainage Features of the Erie and Ohio 
Basins," by Frank Leverett, Monograph 41, U.S.G.S. ; especially 
Chapters 14, 15, 16. 

*159. A RISEN COAST 

San Luis Quadrangle, California. — In what part of 
the state is this region ? How far, and in what direction, 
from San Francisco ? From Los Angeles ? In general, 
along the Pacific coast there has been an elevation of 
the land together with folding. The folding was, in 
general, parallel to the coast. Subsequently there was 
a slight depression. What is the direction of the moun- 
tain ranges ? Are they parallel ? What is the general 
direction of the trend of the coast ? W 7 hat is the general 
height of the coast between San Luis Obispo Bay and 
Morro Bay ? North of Morro Bay ? South of San Luis 
Obispo Bay ? 

Compare the Atlantic City, N.J., coast with this in 
height and smoothness. They are both risen coasts with 
slight subsequent depression. How would you explain 
the differences ? If the folding in the San Luis region 
had been perpendicular instead of parallel to the shore, 



198 MANUAL OF PHYSICAL GEOGRAPHY 

how would the coast probably be different? Sketch good 
examples, showing the differences in the two coasts. Is 
the coast in the vicinity of Morro Bay cut or built ? 
By what is the spit west of Morro Bay covered ? The 
sand has drifted up the sides of the northern end of 
San Luis Mountains for about 700 feet. How are the 
sand slopes different from the other mountain slopes ? 
Why? 

160. A YOUNG RISEN COAST WITH A NARROW COASTAL 

PLAIN 

Nome Special Map, Alaska. — This coast has been 
elevated so as to expose a small line of lowland, prob- 
ably, in part, a former sea bottom. How high is the up- 
land ? How high is the coastal plain at its inner 
margin ? How does this coast differ from the San Luis, 
Cal., region ? Both this coast and the Atlantic City, 
N. J., coast are low, shelving coasts. Which of these two 
is the older in stage of coastal erosion ? Assuming that 
there is no further elevation or depression, how will 
this coast change ? Will it the more or the less re- 
semble the Atlantic City coast ? Why is it so difficult 
and dangerous to land. at Nome during rough weather ? 

161. ELEVATED WAVE-CUT TERRACES AND CLIFFS 

Coast Chart No. 5100, Pacific Coast from San Diego 
to Santa Monica. San Clemente Island. — How far, and 



SHORE LINES AND FORMS 199 

in what direction, from San Diego? This island has 
been elevated several hundred feet. How many ter- 
races on the southern coast ? Do these terraces indi- 
cate a continual uplift or an intermittent uplift? What 
ocean factors produced the terraces ? How wide are 
the various terraces ? How high on the average is the 
island above sea level ? Above the general level of the 
ocean bottom*? 

San Clemente Island is thought to be an elevated and 
tilted fault block. What evidences are there ? What 
similarities in the fault block shown on the Alturas, 
Cal., Quadrangle? In what direction was the tilting? 
How high is the fault scarp above sea level ? How do 
the soundings on opposite sides of the island compare, 
and how do they support the idea of a fault block ? 

References. — San Clemente Island is described by A. C. Law- 
son in Bulletin of the Department of Geology, University of 
California, Vol. I, No. 4; also by W. S. T. Smith, 18th An. Kept. 
U.S.G.S., Part II. 

162. A TIDAL DELTA 

Coast Chart No. 5532, San Francisco Entrance. — 
What rivers enter San Francisco Bay ? Where do you 
think they drop most of their sediment, in the bay or in 
the Pacific ? The average rise and fall of the tide is about 
four feet. Would the incoming tide bring much sedi- 
ment ? Would the outgoing tide ? Why ? What evi- 
dence of the sediment carried by the outgoing tide is to 



200 MANUAL OF PHYSICAL GEOGRAPHY 

be seen west of Golden Gate ? About what is the ra- 
dius of the tidal delta? Is the water deepest at the 
Golden Gate or several miles to the west? How would 
you explain your answer ? How does the shape of this 
delta compare with that of the Mississippi delta ? How 
would you explain their difference ? What is the area 
of the delta ? How many ship channels cross it ? 

163. GENERAL EXERCISE 

Wellfleet and Provincetown Quadrangles, Massachusetts. 
Coast Chart No. 110, Cape Cod Bay. — Note the scales 
of the chart and the quadrangles. How long is Cape Cod 
from the ''elbow" up? What average width? Con- 
trast in all respects the eastern and the western shores. 
Which shore is due largely to destructive action ? What 
are the predominant agents in this action ? Which 
shore is due largely to constructive action? What are 
the predominant agents ? 

Where is Cape Cod highest ? Where lowest ? As the 
mainland in Truro Township retreats westward, what 
change will take place in Salt Meadow and the pond to 
the westward ? How will this change affect Province- 
town Harbor ? How will such a retreat affect the 
position of the spits south of Truro and Wellfleet 
townships ? 

What factors make a harbor at Provincetown ? What 
is its average depth ? Why are there so few good har- 



SHORE LINES AND FORMS 201 

bors on the eastern coast ? Are the islands making the 
series ending in Billingsgate Island disconnected, or are 
they the portions of a feature having some of its parts 
above water ? Is Billingsgate Island likely to be con- 
nected with Great Beach Hill ? Explain your answer. 
How deep is Wellfleet Harbor ? Is it likely to become 
deeper or shallower ? Why ? 

How wide is the platform of wave and current wash 
on the eastern coast ? Make a generalized profile from 
Highlands Life-saving Station about one and a half 
miles seaward. Is the slope between the platform and 
the sea bottom farther out gentle or abrupt? Why? 
How wide, in general, is the submarine platform on the 
western shore ? Which would favor a wide submarine 
platform, strong or weak longitudinal shore currents ? 
What inference can you make as to the strength of 
waves on the eastern and the western coasts ? Sketch 
good examples of spits, hooks, wave-cut cliffs, cliffs and 
associated wing spits, submarine platform, tied island, 
lagoon, tidal inlet, smoothed coast, built coast. (Many 
can be included in one sketch.) 

Hampton Quadrangle, Virginia. — To what coast that 
you have studied is this most similar ? Is it a youthful, 
mature, or old coast ? Where is there a feature similar 
to the Long Branch, N.J., coast ? 

Islip Quadrangle, New York. — From what you have 
learned, discuss Fire Island Beach, Oak Island Beach, 



202 MANUAL OF PHYSICAL GEOGRAPHY 

and Jones Beach ; the shore north of Great South Bay 
and the north shore of Long Island. What significant 
contrast between the two shores ? Would you consider 
Great South Bay a lagoon ? Is it in part filled ? Note 
all the shore forms you can. 



CHAPTER XVI 

HARBORS 
*164. HARBORS. INTRODUCTION 

The following points are important in determining 
the value of a harbor : — 

1. Communication with the back country or the hin- 
terland (by road, railroad, or water). 

2. Deep anchorage. 

3. Deep channel from the anchorage to the sea. 

4. Protection from winds. 

5. Protection from high waves. 

6. Area of the anchorage. 

7. Length of shore line. 

8. Absence of strong tidal currents. 

9. Deep water near the shore. 

10. Possibility of fortification. 

11. Freedom from bars, especially shifting bars. 

12. Freedom from ice. 

State fully and specifically in what respects you 
think these factors are of advantage. What signifi- 
cance has the twelfth factor with respect to Russia ? 
Study each harbor with respect to these factors. 

203 



204 MANUAL OF PHYSICAL GEOGRAPHY 

*165. A DROWNED VALLEY HARBOR. NEW YORK 
HARBOR 

Coast Chart No. 120, New York Bay and Harbor. 
The Lower Bay. — Is there a single entrance ? How 
many ? What is the average depth of water ? What 
is the average depth of the various channels ? Which 
channel will accommodate the larger boats ? 

The Narrows. — How wide ? What is the average 
depth ? What reasons can you give why the Narrows 
are so deep ? What facilities for fortification here ? 
How are they utilized ? 

Tlie Upper Bay. — How wide is the channel that is 
five fathoms deep or over ? How far from the Narrows 
up to the city ? How many square miles of water here 
over five fathoms in depth ? How long a water front 
has New York ? Brooklyn ? Jersey City ? What is 
the combined length ? Is the water deep near the 
shore ? How high is the average tide at Sandy Hook ? 
Governors Island ? Willets Point (on Long Island 
east of Whitestone) ? What features make New York 
Harbor one of the best in the world ? How many of 
the desirable features outlined in the opening paragraph 
has it? Would the Galveston hurricane produce so 
disastrous results here ? Vessels, so far as possible, 
avoid Hell Gate. Why? 



HABBOBS 205 

*166. A EIVER HAEBOR. NEW ORLEANS 

New Orleans Quadrangle, Louisiana. Coast Charts No. 
1007, Gulf of Mexico ; No. 194, Mississippi River from 
the Passes to Grand Prairie ; No. 195, Mississijipi River 
from Grand Prairie to New Orleans. — How does the 
smoothness of the coast in the vicinity of the Mississippi 
compare with the rest of the Gulf coast ? Does the 
coast project near the Mississippi? Why? How much 
does it project? 

The Delta. — What is its shape ? Explain its shape. 
What is the average rise and fall of tide ? What bear- 
ing has this on the shape of the delta? Would you 
infer that there are strong shore currents ? Why ? 
Which of the three main distributaries has the greatest 
average depth of water ? What is its average depth ? 
Which pass is inclosed by jetties? What use have these 
jetties? Do you think they w T ill ever have to be 
lengthened? Why? How are vessels guided to the 
mouth of the pass ? Would any of the bays or sounds, 
such as Bird Island Sound, make good harbors ? Why ? 
Why could not a city be built on the delta itself ? Why 
is a city in this region a commercial necessity ? 

Coast Charts Nos. 194, 195. — How far is New 
Orleans from the ends of the jetties? What is the 
average depth of water up to the city ? The average 
width of navigable water ? 



206 MANUAL OF PHYSICAL GEOGRAPHY 

The Tomographic Map. — What is the general altitude 
of the city as shown by the contours ? Which way 
does the land slope ? Why ? What advantages has this 
harbor ? What disadvantages ? 

*167. A MORAINE HARBOR 

Boston, Mass. Boston and Boston Bay Quadrangles, 
Massachusetts. Coast Chart No. 337, Boston Harbor. 
— Boston Harbor is made by a slightly drowned valley 
and by glacial deposits (many of them drumlins) to 
seaward. 

Is there a single approach ? Why ? Which channel 
is the deepest ? How long is the available water front 
at Boston ? What draught of vessel could not enter 
the harbor ? What facilities for fortification ? For 
construction of lighthouses ? For wind protection 
from the east ? From the west ? Do you think that 
easterly winds would bring high waves to the harbor? 
Why ? How long is the principal channel from the 
harbor to the open sea ? Do you think there is much silt 
and sand brought from the mainland ? Which of the 
factors enumerated in the opening paragraph has Boston 
Harbor ? Which does it lack ? 

*168. A BAR HARBOR 

Coast Charts, Gulf of Mexico, No. 1007, and Galves- 
ton Bay, No. 204. — The coast of Texas is a low, shelv- 



HABBOES 207 

ing coastal plain which has not been depressed to the 
same extent as the coastal plain farther north. From 
the chart of the Gulf of Mexico, determine whether 
Texas, Mexico, and Yucatan have smooth or indented 
coasts. How do they compare in this respect with the 
eastern coast of the United States ? Explain the con- 
trast. How does this coast compare with the Maine 
coast ? Are there off-shore bars ? How long is the 
line of bars? How many inlets from Galveston to 
Point Isabel ? How many miles of bars on the aver- 
age to each inlet ? How does this compare with the 
New Jersey coast ? Does this number of inlets indicate 
strong or weak tides ? Under such conditions, are har- 
bors plentiful ? Why ? What determines the harbors ? 
Do you think such harbors are good ones ? 

Galveston Harbor. — How wide is the bar on which 
the city is built ? How wide is the inlet ? How deep 
is Bolivar Channel ? How long are the jetties on 
either side ? Of what use are they ? How deep is the 
dredged channel along the city front ? How deep is 
Galveston Bay ? Is it suitable for a harbor ? 

Which of the factors enumerated in the opening para- 
graph are favorable to Galveston? Which, unfavorable? 
Which of these factors made the hurricane of 1900 so 
destructive ? What steps have been taken to prevent a 
recurrence of such a disaster (see current magazines) ? 



208 MANUAL OF PHYSICAL GEOGRAPHY 

*169. SAN FRANCISCO HARBOR 

Coast Charts, No. 5500, Pacific Coast from Point 
Pinos to Bodega Head ; No. 5532, San Francisco En- 
trance. — How much of the coast is shown in the small 
scale chart ? Is it a markedly indented coast ? How 
does it compare with the Atlantic coast ? From a gen- 
eral map, determine the number of harbor cities on the 
Pacific coast. How does it compare in this respect with 
the Atlantic coast ? About how long is San Francisco 
Bay ? How wide ? About how many square miles 
does it include ? About what proportion has a depth 
of four fathoms or more ? How wide is the opening 
to the Pacific ? How long ? How deep ? What is 
it called ? 

Where is Mare Island ? For what is it noted ? What 
rivers enter San Francisco Bay ? 

Harbor Chart. — Where is San Francisco located ? 
What city on the opposite side of the bay ? What 
is the depth of water along the San Francisco water 
front ? Along the Oakland water front ? How long 
are the piers on the Oakland front? On the San 
Francisco front ? Why is the water front of San Fran- 
cisco on the northeast instead of the north or the south- 
east side of the city ? 

Compare the harbor in all respects with that of New 
York, Boston, and New Orleans. What railroads have 



HARBORS 209 

their terminus at San Francisco Bay ? What region is 
immediately tributary to this harbor ? 

San Francisco Bay has been termed a rias harbor. A 
rias coast is one somewhat resembling a fiord coast; but 
not caused by glaciation. 

170. A CORAL REEF HARBOR 

* Part I. Key West, Florida. Coast Chart No. 469, 
Key West Harbor. — How far, and in what direction, is 
Key West from Florida ? From Havana ? From New 
Orleans ? Why is a harbor needed in this region ? 
What are the keys and reefs made of ? Do you think 
the keys make high land ? What is the average depth 
of Man-of-War Harbor? About how many square miles 
does it contain ? By how many channels is the harbor 
approached ? What advantages has this harbor ? What 
disadvantages ? Do you think this harbor is used 
because of its excellence or because of its position ? 
What is the mean rise and fall of tides here (see 
Tides) ? How does this compare with New York ? 
Why? 

Part II. Harbor of Apra, Island of Guam. Chart 
No. 1850, Hydrograj)hic Office. — -What is the latitude 
and longitude of Guam Island (see chart) ? How far, 
and in what direction, from San Francisco (measure on 
a globe) ? From Hong Kong ? From Manila ? From 
Honolulu ? What is the average depth of the harbor ? 



210 MANUAL OF PHYSICAL GEOGRAPHY 

About what is its area? How near can ships approach 
Sumay ? Apra ? How many entrances to the harbor ? 
Is the small number of entrances an advantage or a 
disadvantage ? How deep is the entrance ? Would it 
be likely to be as deep if there were more entrances ? 
What beacons determine the paths of entering vessels? 
What is the average height of tide ? How does this 
compare with New York ? Boston ? San Francisco ? 
Is this feature favorable or not ? What cables lead 
from this port ? What strategic value has the island of 
Guam ? What value has the harbor as a naval station ? 
What points of advantage has the harbor ? What dis- 
advantages ? 

*171. A FIORD HARBOR 

Bath Harbor, Maine. Bath Quadrangle, Maine. 
Chart No. 314, Kennebec and Sheepscot Rivers. — In 
what part of the state is Bath ? What is the nature of 
the surrounding country ? What river in the vicinity ? 
How long is this river (see a map of the state) ? 
What is the general shape of the coast ? What is the 
average width of the fiord on which Bath is situated ? 
The average depth of water ? Is there much mud 
and silt at the bottom of Kennebec River ? What 
reasons would account for this ? Is the seaward 
passage straight or crooked ? How does it compare in 
this respect with Boston ? With New York ? Are the 
tides high or low ? What points of advantage has 



HAEBOBS 211 

Bath Harbor? What disadvantages? Why is Bath 
not a commercial center ? 

172. AN ATOLL HARBOR 

Funafuto Atoll. Chart No. 1802, Hydrographic 
Office. — What is the latitude and. longitude of this 
atoll ? How far, and in what direction, from San 
Francisco ? (Measure on a globe.) From Hong Kong ? 
From Manila ? What part of the atoll is used for 
anchorage ? How deep is the water ? How high is 
the land to the eastward of the anchorage ? What 
advantages has this anchorage over other parts of the 
atoll ? How is the anchorage entered ? What general 
advantages of this harbor ? What disadvantages ? 

173. A HOOK HARBOR 

Provincetown Harbor. Provincetoion Quadrangle, 
Massachusetts. Chart No. 110, Cape Cod Bay. — On how 
many sides is this harbor protected by land ? Is it 
protected in directions from which high waves are likely 
to come ? What is the average depth of the harbor ? 
Is the deepest part near the "hook " ? Why ? Can ships 
get near the shore ? Why ? What valuable qualities 
has the harbor ? 

174. A SPIT HARBOR 

Plymouth Harbor. Plymouth Quadrangle, Massachu- 
setts. Chart No. 110, Cape Cod Bay. How long is 



212 MANUAL OF PHYSICAL GEOGRAPHY 

Long Beach ? About how wide is Plymouth Harbor ? 
How deep is the harbor ? Would it be suitable for 
modern commerce ? How many and what valuable 
qualities has this harbor ? 

175. A TIED ISLAND HARBOR 

Marblehead Harbor. Boston Bay Quadrangle, Mas- 
sachusetts. Chart of Salem Harbor, No. 244. — How 
deep is Marblehead Harbor ? In what direction is it 
best protected from winds ? From waves ? Is it deep 
enough for modern commerce ? What closes the 
harbor on the south ? Why is it so shallow at the 
southern end ? 



CHAPTER XVII 

SOILS 

*176. SOILS ALONG AN AGGRADING RIVER 

New Orleans Quadrangle, Louisiana. — Review Exer- 
cise 57. Where is the higher land of the area ? What 
is its origin? What is its type of soil (see soil sec- 



w * 

1 2 | 



3. SANDY LOAM 



Fig. 42. 
Generalized soil section across the Mississippi River through Westwego. 

tion, Figure 42) ? What are the types of soil on 
either side ? What is their origin ? Which soil is most 
easily drained ? 

Sugar cane is largely raised in this region. It 
requires a well-drained soil. Where can it be best 
raised? Rice is also grown. The crop is flooded at 
times. What lands are suitable for this ? 

Reference. — Soil Survey of the New Orleans Area, 1903. 

213 



214 MANUAL OF PHYSICAL GEOGRAPHY 

•177. SOILS ON COALESCED ALLUVIAL FANS 

Cucamonga Quadrangle, California. — Review Ex- 
ercise 60. What is the origin of the alluvial fans? 
What distinction between an alluvial fan and a 
delta ? Which usually is composed of the coarser mate- 
rials? Why? 

From the base of the mountains about to Cucamonga 
and Claremont, are gravels. From this gravel region a 
belt of sands and sandy loams extends nearly to Chino. 

How would you explain this gradation in material ? 
Which belt, do you think, offers the best soils ? Which 
shows the densest population ? 

Before the wash from the mountain streams covered 
the bottom of the valley, the surface was rough. One 
of the old hills stands above the fans in the south- 
western corner of the map. How high does it stand 
above the plain ? It has a loam soil with considerable 
mica. From this, of what would you infer the under- 
lying rock to be composed ? 

The San Gabriel Timber Land Reserve is carefully 
kept covered with timber on account of the effects of 
the timber on the streams. Explain this effect. 

What are the principal agricultural products of south- 
ern California ? 

Keferexce. — Soil Survey of the San Bernardino Valley, Cali- 
fornia, 1904. 



soils 215 

178. VALLEY SOILS DUE TO WASH FROM THE UPLANDS 

Manti Quadrangle, Utah. — The Sevier River Valley, 
in the southwestern part of the quadrangle, is the area 
that has been mapped. How far, and in what direction, 
from Salt Lake City is this region ? What mountains 
on the west ? How deep is the valley ? 

How wide is the valley at the soil section shown in 
Figure 43 ? The rocks of the eastern upland are dark 



5 - 1 ] . 3 n 2 —\ '■ 

1. dark gravelly loam 2. loam (dark) 3. meadow 4. lcam (red) 5. red gravelly loam 

Fig. 43. 
Soil section five miles south of Gunnison. 

crystalline rocks. Those of the valley mountains are 
composed of red sandstone. The loams on the eastern 
side of the valley, are dark and those on the western 
side are red. Why ? Why are the loams on the outer 
margin of the valley gravelly, while those nearer the 
center are not gravelly ? The " meadow " soil is allu- 
vial land. What is the origin of the loams on either 
side of the "meadow" soils? How w T ere they trans- 
ported ? 

Reference. — Soil Survey of the Sevier Valley, Utah, 1900. 



216 MANUAL OF PHYSICAL GEOGRAPHY 

*179. SOILS ON RIVER TERRACES 

Hartford Quadrangle, Connecticut. — Review Exercise 
63. Where are the terraces ? How were they formed ? 
Of what materials are they composed ? Locate the soil 
section shown in Figure 44. The meadows soil is a loam 
with considerable silt and humus. It is subject to over- 
flow by the river. Why should it contain more silt and 
humus than the terrace soils ? Both of these soils are 



1 )2| °\ { 2 |, 1 { 

1. 6ANDY LOAM 2. " MEADOWS" 

Fig. 44. 

Generalized soil section from Wapping through South Windsor to the crest 

of the hill across the Connecticut River. 

extensively used for tobacco growing. Why should 
they be fertile ? 

Reference. — Soil Survey of the Connecticut Valley, 1903. 
♦180. SOILS ON LAKE SHORES AND BOTTOMS 

Berea Quadrangle, Ohio. — Review Exercise 158. 
What is the origin of the ridges ? These ridges have a 
loam soil with considerable gravel and sand. Between 
them are patches of clay and of a loam derived from 
till. Is clay laid down in quiet or active water ? W r hy 
should not the clay be in the ridges? Why should 



soils 217 

there be gravel and sand in the ridges and clay to the 
northward of the ridges ? The till loam is found where 
either the surface was not covered by clay or the clay 
has been eroded. 

Which of these soils have the best drainage? The 
gravel ridges are much utilized for orchards. 

Reference. — Soil Survey of the Cleveland, Ohio, Area, 1905. 
181. SOILS IN A REGION OF RIDGES 

Greenville Quadrangle, Tennessee-North Carolina. — 
What region have you studied that has the same fea- 




1. SHALES. SANDSTONES AND LIMESTONES 2. DOLOMITE ( MAGNESIA N LIMESTONE) 

3. sandstone 4. shales 5. crystalline rocks 

Fig. 45. 

Generalized structure section in the Greenville Region. 

tures ? How are the rocks arranged (see structure 
section, Figure 45) ? What kind of rocks make the 
Holston valley ? Bays Mountain and the parallel ridge 
to the northwest ? The Nolichucky Valley ? Bald 
Mountains ? 

The ridges have a stony loam which contains numer- 
ous sandy bowlders. Why ? What kind of a drainage, 
good or poor, has it ? The soil is subject to leaching. 
Why ? Would such a soil have a high content of lime 



218 MANUAL OF PHYSICAL GEOGRAPHY 

and potash ? Why ? Much of it is left in forest. 
Would such a soil have much humus ? Why ? 

The lowland belts have many clay loams and shale 
loams. The limestone often yields a clay soil. Why? 

References. — Greenville Folio, U.S.G.S.; Soil Survey of the 
Greenville Area, Tennessee, 1906. 

182. ARREDONO QUADRANGLE, FLORIDA 

The soil is sandy. The types differ in the amount of 
humus. One of the best types extends northeast-south- 
west through Gainesville and is about five miles wide. 
This belt is fairly well drained. How ? Another type 
includes more organic matter (humus). These areas of 
soils with humus include the triangular area included 
between the two railroads north of Gainesville, the 
Hogtown Prairie, and the borders of Alachua Lake. 
What drainage features are largely responsible for dif- 
ference in humus ? Which area is most densely popu- 
lated? 

Reference. — Soil Survey of the Gainesville Area, Florida, 
1904. 

183. SOILS ON GROUND MORAINE AND DRUMLINS 

Palmyra Quadrangle, Neio York. — Of what are 
drumlins mainly composed ? They are largely covered 
by a stony loam. What is a loam ? Why stony ? 
What about the drainage of drumlins ? They contain 
many apple orchards. Why ? 



soils 219 

Between the drumlins is low meadow land. Is it as 
well drained as the land in the drumlins ? Peppermint 
and onions are often grown on this soil. 

Reference. — Soil Survey of Lyons Area, New York, 1902. 
*184. SOILS ON A MORAINE AND OUTWASH PLAIN 

Islip Quadrangle, New York. — Review Exercise 
118. What is the cause of the two ranges of hills, the 
plain between them, and the plain to the south ? The 
hills are generally capped by a loamy soil often contain- 
ing numerous bowlders. What is the origin of these 
bowlders? The plains are covered by sand and gravel 
loams and in places by pure sand. What is their 
origin ? 

Truck gardening is the principal agricultural activity 
of Long Island. Why ? Which soils are most easily 
drained ? Which are warmer ? Which are best adapted 
to early vegetables ? Why ? 

In many places the water table is too low for plant 
roots to reach it. What kind of soil would have this 
difficulty ? 

Draw diagram showing the profile. Name the prin- 
cipal topographic features (moraines, etc.), and indicate 
the principal soil types on these features. 

Reference. — Soil Survey of Long Island, New York, 1903. 



CHAPTER XVIII 

STUDIES OP TYPICAL AREAS 

*185. THE RED RIVER VALLEY. A YOUTHFUL LAKE 

PLAIN 

The following grouped maps : 1 Fargo, Casselton, and 
Tower (JST.D.). 

Shade this area on a general map. What is its 
average altitude above sea level ? What variations in 
altitude ? Where is the most nearly level country ? 

A portion of this region was covered by the glacial 
Lake Agassiz. Most of it is underlain by till, but 
where the lake stood the till is, covered by lake sedi- 
ments. In the western part of the area, near Buffalo, is 
a marginal moraine which was not covered by the lake 
waters. Note all the evidences of a moraine. The 
shore line is east of this moraine. What is the slope of 
the shore line ? From Watson to Walcott is the mar- 
gin of a delta that was built into Lake Agassiz. Trace 
its margin. Are its slopes steeper or less steep than in 
the rest of the shore line ? Why ? 

Account for the soil types shown in Figure 46. 
What river drains this plain ? Is the drainage well 
organized ? After a rain, farmers on the level portion 
often have to wait a week for the water to disappear. 

1 For suggestions as to mounting grouped maps, see Appendix. 

220 



STUDIES OF TYPICAL AREAS 



221 



What relation has this fact to the previous question? 
Why can the railroads be built so straight ? 



J 2 J 



1. CLAYS AND CLAY LOAMS 

2. SANDY AND GRAVELLY LOAM3 

3. SAND 

4. LOAMS (DERIVED FROM TILL) 

Fig. 46. 



Beferences. — "The Glacial Lake Agassiz" by Warren Upham; 
Monograph 25, U.S.G.S. ; Soil Survey of the Fargo Area, KD.,1903. 

Bismarck, N.D. 





T. 


p. 


Snow 


R.H. 


January . . . 


7° 


0.7 in. 


5.4 in. 


72.5 


February 








9° 


0.6 in. 


4.9 in. 


74.0 


March . 








22° 


1.0 in. 


7.7 in. 


72.5 


April . 








43° 


2.2 in. 


2.5 in. 


66.5 


May . 








55° 


2.6 in. 


1.4 in. 


64.5 


June . 








64° 


3.6 in. 


0.0 in. 


70.0 


July . 








70° 


2.6 in. 


0.0 in. 


62.5 


August 








68° 


2.1 in. 


0.0 in. 


58.5 


September 






57° 


1.0 in. 


0.0 in. 


65.0 


October . 






44° 


1.1 in. 


0.8 in. 


72.5 


November 






26° 


0.6 in. 


6.3 in. 


75.5 


December 






15° 


0.7 in. 


4.8 in. 


72.5 


Year . . 






40° 


18.8 in. 


34.6 in. 


69.0 



Average dates of last killing frost in spring, May 15. 
Average dates of first killing frost in autumn, September 15. 
Mean annual per cent of possible sunshine, 57. 
General wind direction, N.W. 



222 MANUAL OF PHYSICAL GEOGRAPHY 

Bismarck is the type station for this part of the 
state. How far, and in what direction, is it from 
Fargo ? 

Plot the temperature curve. What is the monthly 
range (difference between the highest and lowest 
monthly temperatures)? When is the maximum? 
The minimum? Is the transition from winter to spring 
and from autumn to winter sudden or gradual ? So far 
as temperature is concerned, is this climate continental 
or marine ? Why ? How long is the season that is 
free from frost ? 

Plot the precipitation curve. When is the maxi- 
mum ? The minimum ? Is the transition between the 
maximum and minimum sudden or abrupt ? This dis- 
tribution of precipitation has been called the Missouri 
type. It is, in general, typical for the Great Plains. 
What percentage of the total precipitation falls in the 
spring ? For how many months, on the average, is there 
snow on the ground ? What percentage of the total 
precipitation is snow ? (On the average ten inches of 
snow make one inch of water.) Is the snow fall heavy? 
Does it, on the average, reach one foot ? What months 
are free from frost ? What is the percentage of possible 
sunshine? Does this, on the whole, indicate sunny or 
cloudy weather ? What general wind direction ? 

The Red River Valley is one of the great spring 
wheat regions of the country. Wheat does best with a 



STUDIES OF TYPICAL AREAS 223 

cool, moist growing season and a dry, sunny, hot ripen- 
ing and harvesting season. What conditions of tem- 
perature, rain, snow fall, and frost do not favor winter 
wheat growing ? What conditions of temperature, pre- 
cipitation, relative humidity, and sunshine favor spring 
wheat ? Extensive wheat growing also demands a sur- 
face on w T hich machinery can be used. How does this 
plain meet this requirement ? 

•186. MATURE AND OLD PLAINS 

Caldwell, Cheney, Kingman, and Anthony, Kan., 
Grouped Sheets. — Shade on a general map the area 
included in this map. In what part of the state is this 
area ? What is the average altitude of this region ? 
What is the principal river ? Into what does it flow ? 
How does this region compare in dissection with the 
Fargo, N.D., region ? How, in stream arrangement 
and organization ? The rocks underlying the region 
are rather weak. How would the hills and valleys 
differ from the present ones if the rocks were strong ? 
What kind of a sky line, level or broken, do you think 
you would see from the hill tops ? Where is there an 
area of sand dunes ? Would you infer from the number 
of towns that the region is productive ? What railroads 
cross the plains here? Why do they run so straight? 

Where are the plains in this region in a mature stage 
of dissection ? Where, in an old stage ? 



224 



MANUAL OF PHYSICAL GEOGRAPHY 



Hot wind at Dodge City, Kan. (Average temperatures 
and relative humidities are given.) 





T. 


R.H. 


Wind 
Velocity 


Wind 
Direction 


State of 
Sky 


September 11, 1882 


72.5° 


31.0 


17 


w. 


Clear 


September 12, 1882 


82.5° 


29.5 


22 


s.w. 


Clear 


September 13, 1882 


78.5° 


31.5 


22 


s. 


Clear 


September 14, 1882 


76.5° 


38.5 


30 


s.w. 


Clear 



How far, and in what direction, is Dodge City from 
the areas shown in the mounted map ? 

Occasionally hot winds blow over the high plains. 
The data for a typical hot wind are given above. 
These are often very destructive to crops because of the 
withering effect. What two factors contribute most to 
this effect ? Is the temperature excessive ? Is the wind 
velocity high or low ? The average relative humidity ? 
What effect have these factors on evaporation ? What 
effect does the state of sky have? What prevailing 
wind direction ? What effect have these directions 
upon temperatures ? Give at least two reasons. 



•187. A SECTION ACROSS NEW YORK. THE ONTARIO 
PLAIN AND THE ALLEGHANY PLATEAU 

The following grouped maps: Sodus Bay, Osivego, Ful- 
ton, Mexico, Syracuse, Baldwinsville, Weedsport, Clyde. 

Geneva, Auburn, Skaneateles, Tully, Cortland, Moravia, 
Genoa, Ovid. 



STUDIES OF TYPICAL ABEAS 225 

Watkins, Ithaca, Dry den, Hartford, Apalachin, 
Oivego, Waverly, Elmira. 

Shade the area on a general map. In what part of 
the state is the area located ? What two physiographic 
divisions in this area ? What is the average width of 
the lowland (Ontario Plain) ? Its average height ? 
Slope? W T hat is the average height of the upland 
(Alleghany Plateau) ? Trace the junction of the plateau 
and plain. Is the boundary distinct? Is it in this 
locality an escarpment? How does it compare in this 
respect with the Niagara region (see Exercise 86) ? 

What is the altitude of Lake Ontario ? How would 
you describe its shore line ? Are the numerous bays 
open ? In general, is it a cliff shore or a built shore ? 
What are the numerous hills (see Exercise 124)? What 
is their average height ? How do they differ from those 
in Wisconsin ? How do those north differ from those 
south ? Trace the outlet of Seneca Lake. W 7 hat dif- 
ferent names has it? Do you think it is a normal 
stream ? Why ? Trace Oneida River. What lake does 
it drain ? To what agency is its peculiar course due ? 
What evidences of glaciation in this region ? Trace the 
northern edge of the plateau. Where is it distinct? 
Where, indistinct ? What is the height of the plateau 
in the lake region? What "finger" lakes traverse the 
plateau? What is the length and average width of 
Lakes Seneca, Cayuga, Owasco, and Skaneateles ? What 



226 MANUAL OF PHYSICAL GEOGRAPHY 

similar valleys are not occupied by lakes ? Which end 
of the lake valleys is partially filled ? How were they 
filled ? Examine the valleys for hanging deltas (see 
Exercise 127). How were these deltas formed? Note 
the valley leading north from Cortland. Where is the 
divide in this valley ? A marginal moraine crosses this 
valley. Locate it. What morainal features has it ? 
Why is a divide so located not a result of normal ero- 
sion ? A moraine crosses the Seneca Valley at Montour 
Falls. Find one south of Ithaca. Can you trace the 
moraine on the upland ? Why is it more distinct in the 
deep valleys ? Find the same feature in Pony Hollow, 
southwest of Ithaca. 

The " finger " lake valleys were scoured and deepened 
by ice erosion. How do they differ from the work of 
normal erosion in inter-valley divides, depth, dissection 
of valley sides, behavior of tributaries, and organization 
of drainage ? 

Near the close of the glacial period, marginal glacial 
lakes were formed in these valleys. Why ? Which way 
would these lakes outflow? Find the outflow channel 
of the lake occupying the Seneca Valley. Describe it. 
Explain the behavior of Catharine Creek (north of 
Horseheads). Account for the abandoned valley of the 
Chemung in the Elmira area (see also Exercise 66). 

Where in this area are the towns and villages most 
frequent ? Where are railroads most numerous ? How 



STUDIES OF TYPICAL AREAS 



227 



would you account for this ? Trace the Erie Canal. 
What physiographic feature does it follow ? From a 
census report of 1890 or 1900, determine the population 
per square mile and the farm values for the following, 
counties included, for the most part, in this area : Che- 
mung, Tioga, Tompkins, Seneca, and Cayuga. Locate 
these counties and account for their population and 
farm values. 

The Ontario plain in its northern portion has a cli- 
matic modification due to Lake Ontario. The same is 
true along the eastern and southern shore of Lake Erie, 
where there is the important " grape belt." 

Average Monthly Temperature at Oswego and Ithaca 





Oswego 


Ithaca. 




Oswego 


Ithaca 


Jan. 


24° 


24° 


Aug. 


68° 


68° 


Feb. 


24° 


25° 


Sept. 


62° 


61° 


March 


31° 


32° 


Oct. 


51° 


50° 


April 


43° 


45° 


Nov. 


39° 


38° 


Mav 


54° 


57° 


Dec. 


28° 


29° 


June 


64° 


66° 


Year 


46° 


47° 


July 


70° 


70° 









First killing frost in autumn : Oswego, October 13 ; Ithaca, Septem- 
ber 24. 

Last killing frost in spring : Oswego, April 25 ; Ithaca, May 22. 

Locate Oswego and Ithaca. What are their alti- 
tudes ? Their difference in altitude ? Plot the tem- 
perature curves for Oswego and Ithaca (use about three 



228 MANUAL OF PHYSICAL GEOGRAPHY 

small squares for each degree). What is the average 
annual temperature for each place ? At which place is 
the change from winter to spring and from autumn to 
winter most abrupt ? Why ? So far as altitude is con- 
cerned, which place would have the coolest spring ? 
What is the length of the season free from frost at the 
two places ? Which has the longest season free from 
frost ? Fully explain your answer. What relation to 
these facts has the location of the fruit and grape belts 
near the lake ? 

*188. THE COASTAL PLAIN, PIEDMONT PLATEAU, AND 
HIGHLANDS IN NEW JERSEY 

The following grouped maps: Trenton, N.J.-Pa., 
Navesink, N.J.-N.Y., Passaic, N.J.-N.T., and Raritan, 
N.J. — Shade on a general map the area of this map. 
What part of the state is included ? 

Looking from the northwest to the southeast corner 
of the map, what highlands and what lowlands do you 
find extending across the region ? Draw a sketch 
map locating New York, Jersey City, Paterson, Morris- 
town, New Brunswick, Trenton, Princeton, and Long 
Branch. Locate also the principal rivers and ridges. 

What kind of rock underlies the different divisions 
of New Jersey (see Figure 47) ? What two kinds of 
rock underly the eastern lowlands (Coastal Plain) ? 
What is the arrangement of these rocks ? What 



STUDIES OF TYPICAL AREAS 



229 



divisions of the Coastal Plain (see Exercise 104) ? Which 
rocks make inner lowlands ? What covers the outer 
slope ? Trace the cuesta. Is it continuous ? Is it 
smooth ? What is its average height ? 

Generally speaking, the Highlands in New Jersey 
include the region between the Coastal Plain and the 




2. SANDS, MARLS AND CLAYS 
5. LIMESTONES 



3. SHALES (TRIASSIC) 4. CRYSTALLINE ROCKS 

B. SEDIMENTARY ROCKS 



Fig. 47. 

Generalized section from Blairstown (Raritan Quadrangle, N.W.) to Point 
Pleasant (Navesink Quadrangle, S.E.). 

ridges in the vicinity of Jenny Jump Mountain. It is 
divided into two parts : the Highlands proper, which 
includes the area of crystalline rocks, and the Piedmont 
Plateau, which is underlaid by shales and sandstones 
(Triassic) (see Figure 47). What is the average height 
of the Highlands? Of the Piedmont Plateau? Is 
there a sharp division between the Piedmont Plateau 
and the Coastal Plain ? Is the slope between them 
gentle or abrupt? On the average, what is the slope 
per mile ? This junction is called the Fall Line. 



230 MANUAL OF PHYSICAL GEOGRAPHY 

What feature in the Delaware River marks this 
junction (above Trenton) ? Why, then, is this line 
called the Fall Line ? What is the origin of the valleys 
in the Highlands (see Figure 47) ? Leaving out the 
valleys, are the altitudes on the Highlands and Pied- 
mont about the same ? 

What are the heights of the First and Second 

Watchung Mountains and of 

i i Long Hill ? What is their 

« origin (see Figure 48) ? The 

ridge on which Jersey City is 

located has the same origin. 



1 /2/ 1 /2/ 1 /2/I 



1. SHALES 3. TRAP ROCKS 



Northwest of Jenny Jump 

Generalized section from Plainfield 

to Pleasant Plains (Passaic Mountain is the Ridge Belt. 
Quadrangle). t J • £ j_i *j 

Judging from the evidences 
shown on the map, what part of this region is glaciated? 
What evidences ? What rivers flow along the inner 
lowland ? What rivers cross it ? Indicate on your 
sketch map the Coastal Plain, Piedmont Plateau, the 
Highlands, and the Ridge Belt. 

Trace the Delaware and Raritan Canal. It was one 
of the first built in this country. What physiographic 
factors favored its construction ? What commercial 
factors ? One of the early railroads was also built in 
the same region. Why? What important railroads in 
this region ? Where are most of the towns and cities ? 

Soils of the Trenton Area. — What soils are found in 



STUDIES OF TYPICAL AREAS 



231 



different divisions of the area (Figure 49) ? Which soils 
are situated for good drainage ? Greensand often 



4 .5 



i , I 



1. SAND 

2. LOAM DERIVED FROM GREENSAND 

3. LOAM SEDIMENTARY IN ORIGIN 

4. LOAM DERIVED FROM SHALES 

6. LOAM DERIVED FROM TRAP ROCKS 

Fig. 49. 



Generalized soil section from Stoutsburg (Trenton Quadrangle, N.W.) to Cassville 
(Navesink Quadrangle, S.W.). 

yields a fertile marly soil. Much of the agriculture on 
the sand is devoted to fruits and truck crops. Why ? 







Seacoast 


Highlands 




Seacoast 


Highlands 




T. 


T. 


T. 


T. 


January . 
February 
March . 
April . . 
May . . 
June . . 
July . . 




30.0° 
30.6° 
38.3° 
48.4° 
59.1° 
68.6° 
73.3° 


26.5° 

26.7° 
35.5° 
48.0° 
59.0° 
67.9° 
71.9° 


August 
September . 
October . . 
November . 
December . 
Year . . . 


72.8° 
67.4° 

56.5° 
45.4° 
35.9° 

52.8° 


70.2° 
63.6° 

51.8° 
40.8° 
31.0° 
49.3° 



First killing frost in autumn: Highlands, October 4; Seacoast, 
October 21. 

Last killing frost in spring: Highlands, May 10 ; Seacoast, April 19. 
Average precipitation : Highlands, 49.1 inches ; Seacoast, 46.6 inches. 

(Soil warmth and drainage are important factors in 

these crops.) 



232 MANUAL OF PHYSICAL GEOGRAPHY 

Beferences. — Soil Surveys of the Trenton, N". J., and of the 
Salem, N.J., Areas. 

Plot the temperatures for the Highlands and the 
seacoast. (Use about three small squares per degree.) 
What differences between the Highlands and the sea- 
coast ? How do the graphs compare with those of 
Oswego and Ithaca ? What average differences in the 
frost season ? Which locality is best adapted for 
melons and truck crops ? Which, for dairying and 
cereals ? How does the frost season compare with that 
of Fargo, N.D. ? How does the total precipitation 
compare with that of Fargo ? What good markets are 
accessible to the farmers of New Jersey ? 

Supplementary : Trace Washington's campaigns in 
this area. What reasons are apparent for his selection 
of Morristown as his base ? 

189. THE COASTAL PLAIN, PIEDMONT PLATEAU, BLUE 
RIDGE, GREAT VALLEY, RIDGE BELT, AND ALLEGHANY 
PLATEAU IN MARYLAND, VIRGINIA, AND WEST VIR- 
GINIA 

The following grouped maps : (Md.) Green Hun, 
Ocean City, Pittsville, Snow Hill, Princess Anne, Salis- 
bury, Nanticoke, Deal Island. 

Crapo, Oxford, Bloodsworth Island, Sharps Island, 
Drum Point, Point Lookout, Prince Frederick, Leonard- 
town, Piney Point, Montr oss, Wicomico, Brandywine. 

(Va.) Fredericksburg, Mount Vernon, Harpers Ferry, 



STUDIES OF TYPICAL AREAS 233 

Warrenton, Spottsylvania, Gordonsville, Luray, Win- 
chester. 

(W. Va.) Pomney, (Va.) Woodstock, Harrisonburg, 
Staunton, ( W. Va.) Franklin, Piedmont, St. George, 
Beverly, Monterey, Buckhannon, Huntersville, Nicholas, 
Sutton. 

What is the length in miles of this strip (note that 
there are two scales) ? Locate it on a general map. 
Shade the area mapped. Make a profile along the par- 
allel of 38°. (Use only the 100-foot contours, and a 
scale of 10 miles to the inch. Let different members 
of the class draw a profile for one quadrangle. The 
different profiles can then be joined. Allow one small 
square to represent 100 feet in altitude.) Where do you 
think the rocks are folded ? Where are they horizontal 
or massive ? Locate Washington, Fredericksburg. 

The Coasted Plain. The Eastern Maryland Maps. — 
Describe the coast line. Where have you seen a similar 
coast ? How wide is the off-shore bar ? With what is 
it largely covered? How wide is the lagoon? How 
would you describe the shore line of the mainland ? 
How would you account for it ? 

What is the width of the region between the Atlan- 
tic and Chesapeake Bay ? What is its average height ? 
Wliat habit have most of the rivers ? How would you 
account for this ? What peculiarity of the shore line 
along Chesapeake Bay ? How wide is Chesapeake Bay 



234 MANUAL OF PHYSICAL GEOGRAPHY 

here? What is the general elevation of the Coastal 
Plain west of the Chesapeake Bay ? Do you think this 
part of the plain is older or younger than the plain east 
of Chesapeake Bay ? Which part is the more dissected ? 
How would their height and relative ages affect their 
dissection ? To what forms is the term neck applied ? 
What is the width of the Wicomico River ? Of Chap- 
tico Bay ? How would you explain these widths ? 

Tlie Piedmont Plateau. — What change in altitude in 
the vicinity of Fredericksburg and Washington ? Here is 
the meeting of the Piedmont Plateau and the Coastal 
Plain. Trace this line across the map (the Fall Line). 
What is its average slope? What feature on the Po- 
tomac near the Fall Line ? What similar feature on 
the Delaware (see Exercise 188) ? What, on the James 
in Richmond (see Richmond Quadrangle) ? Compare 
the rivers and their valleys on either side of the Fall 
Line. The Piedmont Plateau extends westward to the 
Blue Ridge. How would you describe the Piedmont 
Plateau, as level, rolling, or mountainous ? How does 
it compare in this respect with the Coastal Plain ? The 
plateau has been peneplained and subsequently elevated. 
What evidence of this is found in the valleys, in the 
altitudes, and in such monadnocks as Mount Pony and 
Thoroughfare Mountain ? 

Tlie Blue Ridge, Great Valley, and Ridge Belt. — How 
wide is the Blue Ridge on the average ? What is 



STUDIES OF TYPICAL AREAS 235 

its average height ? Where is it narrowest ? Which 
margin, the east or the west, is steeper ? Which mar- 
gin is more distinct ? What direction is its trend ? 
West of the Blue Ridge is the Great Valley and the 
belt of Appalachian Ridges. How wide is the Great 
Valley? How deep below the Blue Ridge is it? 
What river drains it? Does it widen or narrow to 
the southward ? 

What is the average width of the Ridge Belt ? How 
many ridges in its northern part ? Southern part ? 
What is the trend of the ridges ? What is their aver- 
age height above the valleys ? Above sea level ? 

What is the drainage pattern in this belt ? Where 
are most of the roads and railroads ? Where do the 
roads cross the ridges ? Why are the roads so crooked ? 
Are the openings in the ridges wind gaps or water gaps, 
or both ? What is the origin of the wind gaps (see Ex- 
ercise 98) ? What is the probable origin of the water 
gaps (see Exercise 76)? 

Is the transition from this belt to the plateau west- 
ward gradual or abrupt ? The Alleghany Front is usu- 
ally taken as the western boundary of the Ridge Belt. 
What is its structure (Figure 50) ? Why does this 
structure cause an escarpment? How are the rocks 
arranged west of the Alleghany Front ? What causes 
Backbone Mountain and Hoop Pole Ridge? Where 
have you seen a similar example (Exercise 92) ? 



236 MANUAL OF PHYSICAL GEOGRAPHY 

TJie Alleghany Plateau. — What is the average eleva- 
tion above sea level ? How does its dissection compare 
with that of the Piedmont ? Of the Coastal Plain ? 
What, would you infer, is the arrangement of its rocks, 
horizontal or folded ? What is the general stream pat- 
tern ? Are the ridges and valleys parallel, as in the 




2. sandstone (pocgnoj 
Fig. 50. 



Section through Hoop Pole Ridge across the Alleghany Front. 

Ridge Belt ? Why ? In what stage of dissection is the 
surface ? Compare the stream patterns and the topog- 
raphy in the Alleghany Plateau, the Ridge Belt, and 
Coastal Plain. Illustrate with a contour sketch of six- 
teen square miles a type area in each division. 

Where are the roads found in each division? Explain 
the peculiarity of road location on the Coastal Plain. 
Where is most of the population ? What reasons ? 

Supplementary: How is the Shenandoah Valley 
separated from the Piedmont Plateau ? On a general 
map, trace the Shenandoah River. Work out the influ- 
ence of this valley on various campaigns of the Civil 
War. See " Geographic Influences in American History," 



STUDIES OF TYPICAL AREAS 237 

by A. P. Brigham, Chapter 7 ; " American History and 
its Geographic Conditions," by Ellen C. Semple, Chapter 
14 ; and Journal of School Geography, June, 1901. 

*190. THE PIEDMONT PLATEAU, BLUE RIDGE, APPALA- 
CHIAN VALLEY, CUMBERLAND PLATEAU, AND NASH- 
VILLE BASIN 

The following grouped maps: (W.C) Yadkinville, 
Statesville, Hickory, Wilkesboro, Cranberry, Morgantown 
{note that some of these maps have different contour 
intervals). 

Roan Mountain, Mount Mitchell, Saluda, Pisgah, 
Ashville, (Tenn.) Greenville, Morristown, Mount Gkiyot, 
(N.C.) Cowee, Nantahala, [Tenn.) Knoxville, Maynards- 
ville. 

Briceville, Loudon, Murjihy, Cleveland, Kingston, 
Wartburg, Standing stone, Pikeville, Chattanooga, Seiva- 
nee, McMinnville. 

What is the latitude of these maps ? The longitude ? 
How do they compare in latitude and longitude with 
the maps in Exercise 189 ? Locate these maps on a 
general >map, and shade their location on a blank map. 

The Blue Ridge. — Trace the eastern border of the 
Blue Ridge. How does it compare in smoothness with 
the same feature in Virginia? In distinctness? In 
height ? Are each of the indentations in the Blue Ridge 
occupied by a stream ? To what are the indentations 



238 MANUAL OF PHYSICAL GEOGRAPHY 

due ? Trace the Yadkin River ; the New River ; the Ca- 
tawba River ; the French Broad River ; the Nolichucky 
River. Into what do they flow ? Is the Blue Ridge a 
divide? Is it in Virginia? Which way in Virginia do 
the streams on either side of the Blue Ridge ultimately 
flow ? In what way do they in this region ? On which 
side of the Blue Ridge is the divide in North Carolina 
and in Virginia? What outliers from the Blue 
Ridge ? 

Trace the valley of the French Broad River. Where 
is it wide ? Where, narrow ? About how many square 
miles in the Asheville Valley ? Find similar and smaller 
intermontane valleys. 

Trace the westward-flowing rivers of the Blue Ridge. 
Which are steeper, their upper or lower courses ? How 
do the valleys in their upper and lower courses com- 
pare ? In like manner, trace the eastward-flowing 
rivers. How would you describe the western border of 
the Blue Riclge ? The Unaka Mountains are an off- 
shoot of the Blue Ridge. What names do they bear in 
this region ? How does the western border compare 
with the same feature in Virginia ? 

How wide is the Blue Ridge Belt ? What is the av- 
erage height ? Describe the surface. How does its 
width here compare with its width in Virginia ? In 
New Jersey ? (The Highlands in New Jersey are the 
counterpart of the Blue Ridge.) 



STUDIES OF TYPICAL AREAS 239 

Draw a sketch map of the Blue Ridge Belt, showing 
the principal rivers, mountains, towns, and railroads. 

The Great Valley. — How wide, on the average, is the 
Great Valley ? Where is it least interrupted by ridges ? 
What river drains it ? 

TJie Ridge Belt. — How wide is the Ridge Belt ? 
What is the average height of the ridges above the 




1. limestone 2. sandstone 3. limestone 4. sandstone 

Fig. 51. 
Generalized section from the Great Valley, through the Nashville Basin. 

valley ? Above sea level ? What ridges are nearly or 
quite continuous through the area? What ridges have 
even crests ? Which consist mainly of a line of hills ? 
Which of these two classes of ridges, do you think, is 
sandstone or strong rock ? Which is limestone ? Com- 
pare the Ridge Belt with that in Virginia. What rivers 
unite to form the Tennessee ? What city near their con- 
fluence ? What escarpment bounds the Ridge Belt on 
the west ? What is its structure (Figure 51) ? Compare 
it in structure and height with the Alleghany Front. 
How is the course of the Tennessee River in the valley 
and in the plateau somewhat peculiar ? What geo- 
graphic factors in the location of Chattanooga ? Why 



240 MANUAL OF PHYSICAL GEOGRAPHY 

was it a place of high strategic importance in the Civil 
War ? What is the origin of the Sequatchie Valley 
(Exercise 91) ? 

The Cumberland Plateau. — What is the average 
height of the Cumberland Plateau? With what plateau 
does it correspond in West Virginia ? In New York ? 
How do the valleys of the plateau and the Great 
Appalachian Valley compare in width, cross section, 
and depth ? How is the valley cross section in the 
plateau to be explained by the plateau structure (see 
Exercise 82) ? (The plateau surface is underlain by a 
stratum of sandstone beneath which is limestone.) 
How much below the general average height of the 
plateau is the Great Valley ? Compare the eastern and 
western margins of the eastern part of the Cumberland 
Plateau. 

The Nashville Basin. — West of the Cumberland 
Plateau is the Nashville Basin. The escarpment over- 
looking this basin is called the Highland Rim. Trace 
this escarpment from McMinnville to Standingstone. 
How does it compare with the Niagara escarpment ? 
The Alleghany Front ? The Cumberland escarpment ? 
What causes its uneven front ? What keeps the escarp- 
ment steep (see Exercise 86 and Figure 51)? The 
Nashville Basin is underlain with limestone. W T hat kind 
of a soil has the basin ? The plateau ? Wliich, do you 
think, is the more fertile? 



STUDIES OF TYPICAL ABEAS 241 

If you have the Nashville Quadrangle, note the 
western boundary of the Nashville Basin. Where is 
the Highland Rim ? How high is it ? Compare its 
surface with that of the Nashville Basin. 

Tlie Cumberland Gap. Cumberland Gap Quad- 
rangle. — - Locate this quadrangle with reference to 
your grouped maps. Locate Cumberland Gap. What 
three states have a junction near the gap ? Through 
what mountain does the gap give a passage ? How 
far below the crest of the mountain is the floor of the 
gap ? What river leads to the gap from the east ? 
What, from the west ? From a general map of the 
region, trace these rivers. To what is Powell River 
tributary ? Cumberland River ? Make a sketch map 
showing the relation of the rivers to the gap. Thou- 
sands of pioneers passed westward through this gap. 
Why ? 

What streams head near the gap ? What does this 
fact suggest as to its origin ? Where have you seen 
similar examples (Exercise 88) ? 

Read the chapters pertaining to the route through 
Cumberland Gap in Hurlbut's "Cumberland Road." 

Plot the temperature curves for Nashville, Asheville, 
and Atlanta. . Plot the precipitation curves for Nash- 
ville and Atlanta. How do they compare with that of 
Fargo, N.D. ? The curve for Nashville is typical in 
general for the North and South Atlantic states, the 



242 



MANUAL OF PHYSICAL GEOGRAPHY 



Ohio Valley, and the Appalachian regions. How would 
you account for differences in temperature between 
Nashville and Asheville (note the elevations) ? 





Asheville, 
N.C. 


Nashville, Tenn. 


Atlanta, Ga. 


T. 


T. 


p. 


T. 


P. 


Jan. 


38° 


38° 


4.8 in. 


42° 


5.3 in. 


Feb. 


40° 


41° 


4.8 in. 


46° 


5.2 in. 


March 


46° 


49° 


5.3 in. 


52° 


5.9 in. 


April 


54° 


59° 


4.6 in. 


61° 


3.7 in. 


May 


63° 


68° 


3.5 in. 


70° 


3.3 in. 


June 


69° 


76° 


4.2 in. 


76° 


4.0 in. 


July 


72° 


80° 


4.4 in. 


78° 


4.8 in. 


Aug. 


71° 


78° 


3.4 in. 


77° 


4.5 in. 


Sept. 


65° 


71° 


3.7 in. 


72° 


3.0 in. 


Oct. 


54° 


60° 


2.3 in. 


62° 


2.3 in. 


Nov. 


45° 


48° 


3.8 in. 


52° 


3.5 in. 


Dec. 


39° 


41° 


3.8 in. 


44° 


4.4 in. 


Year 


55° 


59° 


48.6 in. 


61° 


49.9 in. 



First killing frost in autumn : Asheville, October 20 ; Nashville, 
October 24; Atlanta, November 7. 

Last killing frost in spring : Asheville, April 22 ; Nashville, April 2 ; 
Atlanta, March 24. 

Some cotton has been grown in the Nashville Basin. 
Atlanta is the center of an important cotton-growing 
region. Cotton needs during the growing season four 
to five months of high temperature and abundant 
rainfall. During the ripening season, high temperature 
and dryer weather are needed while wet weather during 



STUDIES OF TYPICAL AREAS 243 

the picking season is destructive. Killing frosts should 
not come later than April 1 or earlier than Novem- 
ber 1. Compare in all these respects the tables for 
Nashville and Atlanta. Why cannot cotton be 
grown in North Dakota ? Can wheat be grown in 
Tennessee ? 

From a census report, find the population, farm 
values, average size of farms, and farm products of 
the following counties : Yadkin, N.C., Wilkes, N.C., 
Watauga, N.C., Carter, Tenn., Greene, Tenn., Hamblen, 
Tenn., Grainger, Tenn., Union, Tenn., Anderson, Tenn., 
Morgan, Tenn., Davidson, Tenn. Which are wholly 
in the Blue Ridge Belt ? Which, in the Appalachian 
Valley? Which, in the valley of the Tennessee? Which, 
in the Cumberland Plateau ? (Different members of 
the class may be assigned different counties.) 

Along the parallel of 35° 30', make a profile across 
the region of these maps. Use only the 100-foot con- 
tours and a scale of three miles to an inch. It would 
be well for each student to draw the profile for one 

quadrangle. These profiles can be pasted together. 

i 

References. — "The Southern Appalachians" in the "Physi- 
ography of the United States " ; Soil Survey of Davidson County, 
Tenn., 1903. 

Siqyplementary : Study the campaigns of the Civil 
War in the vicinity of Chattanooga. You will find a 



244 MANUAL OF PHYSICAL GEOGRAPHY 

close relation between the physiography of the region 
and the movements of the armies. 1 

191. A PORTION OF THE RIDGE BELT AND THE GREAT 
VALLEY IN PENNSYLVANIA 

The following grouped maps : {Pa.) Swibury, Shamo- 
kin, Catawissa, Pine Grove, Lykens, Mittersburg, Mil- 
lerstown, New Bloomfield, Ilarrisburg, Hummelstown, 
Lebanon. 

*Part I. — Shade this area on a general map. In what 
part of Pennsylvania is it located ? How far, and in 
what direction, from Philadelphia ? What physiographic 
areas shown here ? Locate the Great Valley. The 
Ridge Belt. What boundary of the Great Valley south- 
east of Lebanon ? Review Exercises 92 and 93. Trace 
Blue Mountain, Second Mountain, Third Mountain. 
How does Third Mountain change as you trace it east- 
ward ? Trace Peters Mountain. What different names 
does it bear ? What is its length ? 

From the structure section, Figure 52, determine the 
anticlines and synclines and the topography resulting 
from them. Note the Shamokin and Wiconisco coal ba- 
sins. Are these basins in anticlines or synclines? The 
coal measures once covered the entire region. Why do 

1 See Chapter 14 in " American History and its Geographic Condi- 
tions " ; Journal of Geography, February, 1905, or Popular Science Monthly, 
June, 1901; Grant's Memoirs, Vol. II; Chapter 7 in "Geographic Influ- 
ences in American History." 



STUDIES OF TYPICAL AREAS 



245 



they not at present ? Where are towns most numerous ? 
Why ? Find longitudinal and transverse valleys. Find 
water gaps and wind gaps. 



JLJ. 



^g?7 






Fig. 52. 

Generalized section from Peters Mt. through Little Mt. (Lykens and Shamokin 

quadrangles). 

Part II. — Note the principal anticlines and syn- 
clines, and determine whether their axes are horizontal 
or pitching ; and if pitching, in what directions do their 
axes pitch ? Trace the peneplain described in Exercise 
100. In which direction does it slope ? In what stage 
of erosion would you class this region ? Are the streams 
mostly adjusted ? Find examples of adjusting streams 
(see Exercise 97). Note the Conodoguinet and Swatara 
Creeks. Would you expect them to meander with their 
present volume and grade ? Why ? How can their me- 
andering be explained (see Exercises 75 and 76) ? Does 
the Susquehanna River take an easy course ? What is 
the probable explanation (see Exercise 76) ? Find other 
examples of the same class. 



246 MANUAL OF PHYSICAL GEOGRAPHY 

192. THE COASTAL PLAIN" IN FLORIDA 

The following grouped sheets of Florida : Williston, 
Citra, Dunnellon, Ocala, Tsala A/popka, Panasoffkee. 
Review Exercises 138 and 182. 

In what part of the state is this region ? On a gen- 
eral map, shade the region of the maps. What direction 
is this region from St. Augustine ? On a general map, 
trace the YVithlacooch.ee River. What part of its course 
is shown in this map ? What is the principal town ? 
What is the average altitude above sea level ? What is 
the highest surface ? The lowest surface ? Would you 
describe the surface as level or rolling ? How does it 
compare with the outer part of the Maryland Coastal 
Plain ? The inner (western) part ? With a lake plain 
(Fargo, N.D.) ? 

Would you describe the drainage as good or poor ? 
Organized, unorganized, or disorganized ? Do you think 
the lakes along the streams are deep ? Do you think 
they have the same origin as those in the Bayou Sara 
region (Exercise 62) ? 

In what respects does the topography west of Ocala 
resemble morainic topography ? How does it differ ? 
What is the origin of many of the streams, especially 
the Wekiwa Creek and Dead River (southwestern 
part) ? Into what do many of the small creeks empty 
(e.g. Brooks Branch, northwest of Ocala)? Would you 



STUDIES OF TYPICAL AREAS 



247 



describe the dissection of the region as youthful, mature, 
or old ? What mines north of Ocala ? For the soils of 
this region, review Exercise 182. 

Tampa, Fla. (Elevation 17 Feet) 





T. 


p. 




T. 


p. 


January . . 


59° 


2.8 in. 


Augus ; : . . 


82° 


8.4 in. 


February . 


62° 


3.5 in. 


September . 


80° 


8.2 in. 


March . . 


67° 


2.9 in. 


October 


74° 


2.8 in. 


April 


70° 


2.1 in. 


November . 


67° 


1.7 in. 


May . . . 


76° 


2.4 in. 


December . 


61° 


1.8 in. 


June . . . 


80° 


8.5 in. 


Year . . . 


72° 


53.1 in. 


July . . . 


81° 


8.0 in. 









First killing frost in autumn, January 9. 
Last killing frost in spring, February 8. 

How far, and in what direction, is Tampa from Ocala? 
What is their difference in altitude ? Plot the tempera- 
tures for Tampa. How does your graph compare with 
that for Bismarck, N.D. ? Nashville, Tenn. ? Which 
region has the greatest monthly temperature range ? 
The most abrupt changes between seasons? Plot the 
precipitations for Tampa. When is the maximum? 
The minimum ? How does the graph compare with 
that for Nashville ? For Bismarck ? If this type of pre- 
cipitation occurred in Dakota, would it be more or less 
suitable than the present type ? Why ? 

What is the length of the frost season at Tampa ? 
How does this compare with Nashville and Bismarck ? 



248 



MANUAL OF PHYSICAL GEOGRAPHY 



Florida is noted for its oranges and truck crops. 
What climatic features favor these crops ? 



*193. THE LOWER MISSISSIPPI VALLEY 

(Review Exercise 176) 

New Orleans 





T. 


p. 




T. 


p. 


January . . 


54° 


4.6 in. 


August . . 


82° 


5.7 in. 


February . 


57° 


4.7 in. 


September . 


79° 


4.7 in. 


March . . 


63° 


5.2 in. 


October 


70° 


3.0 in. 


April . . 


69° 


5.1 in. 


November . 


61° 


3.8 in. 


May . . . 


75° 


4.0 in. 


December . 


55° 


4.3 in. 


June . . . 


81° 


6.2 in. 


Year . . . 


69° 


57.6 in. 


July . . . 


83° 


6.3 in. 









First killing frost in autumn, December 15. 
Last killing frost in spring, January 24. 
Mean annual percentage of possible sunshine, 53. 
Mean annual relative humidity, 77. 

Plot the temperature and precipitation for New 
Orleans. What curves that you have made do they 
resemble ? What is the length of the frost season ? 
Can corn be grown here ? Wheat ? Sugar cane 
requires high temperature, ample rain, strong sunlight, 
and fertile soil. What climatic factors in Louisiana are 
favorable to sugar cane, and why ? 



STUDIES OF TYPICAL AREAS 249 

*194. SOUTHERN NEW ENGLAND. CONNECTICUT 

The following grouped maps: (Conn.) Putnam, Moo- 
sup, Stoning ton, New London, Norwich, Woodstock, 
Tolland, Gilead, Saybrook, Guilford, Middletoivn, 
Hartford, Granby, Meriden, New Haven. 

Winsted, Waterbury, Derby, Bridgeport, Norwalk, 
Danbury, Neiv Milford, Cornwall, ( Conn.-N. T.) Middle- 
brook, Clove, Caramel (N Y.), Stamford. 

Taking the state as a whole, what uplands ? What 
lowlands ? What percentage of the state is upland ? 
What is the general altitude and slope from the northern 
part to the sea ? Of the upland west of the Housa- 
tonic River ? Between the Housatonic and the Con- 
necticut ? East of the Connecticut ? Compare the 
surfaces of these three uplands. How wide are the 
respective highlands and lowlands ? Locate New 
London, Hartford, New Haven, Middletown, Danbury, 
Bridgeport. 

Trace the Connecticut River. Trace the lowland 
through which the Connecticut flows to Middletown. 
Does the Connecticut follow the lowland from Middle- 
town to the sea ? Where does the lowland reach the 
sea ? The lowland is largely composed of sandstone, 
and the uplands of crystallines. Compare and explain 
the width, depth, and sides of the Connecticut Valley 
in the lowland and in the upland. Does the river 



250 MANUAL OF PHYSICAL GEOGRAPHY 

appear to take the easiest course ? What similar 
example have you seen ? In like manner, trace the 
lowland in which, for a distance, the Housatonic River 
flows, and also the river valley. How many linear ridges 
in the Connecticut Valley ? What is their origin (see 
Figure 34) ? Describe the slopes of these ridges. Are 
the slopes symmetrical ? Aside from the valleys of the 
Connecticut and the Housatonic, describe the river val- 
leys as to width, side slopes, and stage in erosion. 
In what stage of erosion would you say the surface of 
Connecticut is ? Has the surface been glaciated ? What 
are the evidences ? Southeast of Westerly (southeast 
corner of the map) is a well-defined moraine. Locate 
and trace the moraine. What characteristics does it 
have ? Has it an outwash plain ? How does it differ 
from the adjacent country ? How can you infer the 
ice-contact side ? How would you describe the rivers in 
their lower courses ? What other examples have you 
seen? How are they to be explained? To what type 
of sea coast does that of Connecticut correspond ? Is 
it favorable for harbors ? What physiographic areas 
include most of the cities ? Compare the density of 
population, farm values, crops, and manufactures in 
these counties along the northern border of the state : 
Litchfield, Hartford, Tolland, and Windham. (See cen- 
sus reports of 1900.) Which are largely upland coun- 
ties ? Which lowland ? 



STUDIES OF TYPICAL ABE AS 



251 



References. — " Physical Geography of Southern New Eng- 
land," W. M. Davis, in "Physiography of the United States"; 
Soil Survey of the Connecticut Valley, 1903 ; Holyoke, Mass. 
Polio, U.S.G.S. 

New Haven 





T. 


P. 


Snow 




T. 


p. 


Snow 


January- 


28° 


4.0 in. 


10.0 in. 


August 


70° 


4.9 in. 


0.0 in. 


February 


29° 


4.0 in. 


11.2 in. 


September 


64° 


3.6 in. 


0.0 in. 


March 


35° 


4.5 in. 


8.1 in. 


October 


53° 


3.9 in. 


*T 


April 


46° 


3.5 in. 


1.3 in. 


November 


41° 


3.7 in. 


3.3 in. 


May 


58° 


3.7 in. 


♦ T 


December 


32° 


3.5 in. 


6.4 in. 


June 


66° 


2.9 in. 


0.0 in. 


Year 


50° 


47.2 in. 


40.3 in. 


July 


72° 


5.0 in. 


0.0 in. 











* " T " indicates an amount too small to measure. 

Average date for first killing frost in autumn, New Haven, October 17. 
Average date for first killing frost in autumn, New England, Septem- 
ber 23. 
Average date for last killing frost in spring, New Haven, April 20. 
Average date for last killing frost in spring, New England, May 12. 
Mean annual relative humidity, New Haven, 75. 

Plot the temperatures for New Haven. What is the 
maximum ? Minimum ? The monthly range ? Is the 
change from summer to winter and from winter to 
summer gradual or abrupt ? How does the graph com- 
pare in this respect with New Orleans and Tampa ? 
How do the mean annual temperatures of these three 
places compare ? 

Plot the precipitation for New Haven. How does 
your graph compare with that of Bismarck and New 



252 MANUAL OF PHYSICAL GEOGRAPHY 

Orleans ? Which graphs show the most variation in 
rainfall from month to month ? The least ? This dis- 
tribution of rainfall, on the average, is typical for New 
England. What effect, favorable or unfavorable, has 
such a distribution of rainfall on the water power of 
New England rivers ? 

In what months does snow fall ? How long is the 
snow season ? What percentage of the total precipita- 
tion is snow ? Does this percentage indicate much or 
little rain in the winter ? How does New Haven com- 
pare in this respect with Bismarck, S.D. ? 

What is the length of the frost season for New Eng- 
land ? For New Haven ? How would you explain the 
difference ? What differences in other climatic factors in 
New Haven and New England ? What explanation can 
you suggest ? How does the relative humidity compare 
with that of Bismarck ? Would cotton grow in New 
England ? Why ? Would wheat ? Why ? 

195. THE BLACK HILLS AND THE GREAT PLAINS 

The following grouped maps : (S.D.) liajrid, Hermosa, 
Oelrichs, Edgemont, Harney Peak, Deadivood, (Wyo.) 
Sundance, Newcastle. 

Shade this area on a general map. How far, and in 
what direction, is this region from Fargo ? From Chi- 
cago ? What states are included ? How many prin- 
cipal areas of highlands and lowlands ? How high, in 



STUDIES OF TYPICAL ABE AS 253 

general, is the Plains area ? The Black Hills area ? 
Locate Rapid, Custer, Spearfish, Cheyenne River. Into 
what does this river flow ? (See general map.) 

Trace the elevation, beginning at Sturgis, near Rapid, 
through Hot Springs, Newcastle, and Sundance. Where 
is it most distinct ? Where least distinct ? Where is it 
widest ? What is its average width ? Average height ? 
Are its slopes equal ? What similar ridge have you 
studied (see Exercise 103) ? 

In like manner trace the valley west of Sturgis. 
Where is it widest ? Where narrowest ? What is its 
average width in the eastern part of the region ? The 
southern part ? The western part ? What is its aver- 
age depth below the outer ridge ? Is this valley occu- 
pied by a river ? 

The inner area consists of a limestone plateau sur- 
rounding a deeply dissected plateau of crystalline rocks. 
Trace each area. About how large an area is included 
in the hilly portion of the map ? How does the Black 
Hills surface compare with the Plains surface? 

Make a profile east and west across the area about 
four miles north of Rapid. Correlate this profile with 
the structure section (Figure 53). 





2. SANDSTONE (DAKOTA) 3. CRYSTALLINE ROCKS 

Fig. 53. 



East-west Section across the Black Hills near Rapid, S.D. (After Dart on.) 



254 MANUAL OF PHYSICAL GEOGRAPHY 

How do you account for the steep slopes of the outer 
ridge (hogbacks) ? The inner circular valley ? The 
high central region ? 

From the drainage, what can you infer as to the 
rainfall of the Black Hills as compared with the Plains ? 
How much higher are the Black Hills than the Plains ? 
What is the origin of the name, Black Hills ( see an 
encyclopedia) ? The Black Hills are the catchment 
region for much of the artesian water of the Plains. 
Explain this fact (see Figure 54). Why are the sand- 




1. SHALES 2. SANDSTONE (DAKOTA) 3. CRYSTALLINE ROCKS 

Fig. 54. 
Generalized Section from the Black Hills across the Plains towards Yankton, 
S. D. The Dakota sandstone is the main water-bearing stratum. (After 
Darton.) 

stones better water carriers than shales ? Of what use 
in this connection are the overlying shales ? The under- 
lying shales ? 

Problem. — Why is the "hogback," formed by the 
Dakota sandstone, wider on the west side of the Black 
Hills than on the east side (see structure section ; also 
Exercise 99) ? 

How would you account for the number of towns in 
the Black Hills as contrasted with the Plains ? 

References. — "The Southern Half of the Black Hills," N. H. 
Darton, 21st annual report, U.S.G.S., Part IV, pp. 489-598. 



STUDIES OF TYPICAL AREAS 



255 



The following U. S. G. S. Folios : Edgemont, S.D., Oelrichs, 
S.D., Newcastle, Wyo. (Any one of these folios will give a brief 
description of the Black Hills region.) 

Black Hills and Plains 





Spearfish, S.D. 


Oelrichs, S.D. 




Altitude, 3647 Ft. 


Altitude, 3339 Ft. 




T. 


p. 


T. 


p. 


January .... 


25° 


1.0 in. 


23° 


1.1 in. 


February . 








21° 


1.0 in. 


20° 


1.2 in. 


March . . 








30° 


2.2 in. 


31° 


2.1 in. 


April . . 








46° 


3.0 in. 


46° 


2.2 in. 


May . . 








55° 


3.0 in. 


57° 


2.8 in. 


June . . 








64° 


4.1 in. 


66° 


3.1 in. 


July . . 








71° 


2.0 in. 


73° 


2.0 in. 


August 








70° 


1.6 in. 


72° 


1.0 in. 


September 








60° 


1.1 in. 


60° 


1.0 in. 


October . 








49° 


1.3 in. 


48° 


1.2 in. 


November 








35° 


0.6 in. 


33° 


0.8 in. 


December 








31° 


0.9 in. 


26° 


0.8 in. 


Year . . 








46° 


21.8 in. 


46° 


19.3 in. 



Plot the precipitation for Spearfish and Oelrichs. 
Locate these places on the map. What difference in al- 
titude ? In precipitation ? How would you explain 
the difference in precipitation ? 



*196. THE EASTERN MARGIN OF THE ROCKY MOUN- 
TAINS AND THE ADJACENT GREAT PLAINS 

The following grouped maps in Colorado : Pikes Peak, 
Colorado Springs, Big Springs, Canon City, Pueblo, 
Nepesta, Huerfano Park, Walsenburg, and Apishapa. 



256 MANUAL OF PHYSICAL GEOGRAPHY 

In what part of the state is this region ? On an 
outline map, shade this area. What two principal areas 
appear ? What average height has the Plain near the 
eastern margin of the map ? At the western margin of 
the Plain ? What direction does it slope, and at what 
average rate ? How would you describe the dissection 
of the Plain ? What is the general height of the Rocky 
Mountains in this region ? Is their meeting with the 
Plains straight or indented ? What ridges south of 
Colorado Springs ? What is their origin (see Exercise 
103) ? Trace these ridges. What spur extends into 
the Plain west of Pueblo ? 

How high is Pikes' Peak ? How does its height com- 
pare with that of Mount Mitchell ? Is Pikes Peak an 
isolated peak or a part of a range ? How high is it 
above the general altitude of Pikes Peak Range ? 
How high above Colorado Springs ? Note the various 
parks in the Rocky Mountain Range. What important 
rivers rise in this vicinity ? Is the mountain region, in 
general, densely populated ? What is the reason for 
the group of towns around Cripple Creek ? 

*197. THE EASTERN BORDER OF THE GREAT BASIN 

The following grouped maps : ( Utah) Ashley, Uinta, 
Salt Lake, Toole Valley, Sevier Desert, Manti, Price 
River, East Tavaputs. 



STUDIES OF TYPICAL AREAS 257 

In what part of the state is this region ? Shade the 
area on an outline map. What two physiographic di- 
visions ? The mountainous division is in the Colorado 
Plateau; the Plains division is in the Great Basin. 
What mountains form the boundary between the 
Plateau and the Great Basin ? What mountains per- 
pendicular to the Wasatch Range ? What are the 
heights of these ranges ? One of these ranges is due to 
an anticlinal folding and the other is a fault scarp 
(Exercise 105). From their slopes infer the origin of 
each range. What causes the abundance of lakes in 
the Uinta Mountains (Exercise 116) ? How would you 
describe the dissection of the Plateau ? 

What is the average altitude of the Plain ? How far, 
on the average, is it below the Wasatch Mountains ? 
What mountains rise above the Plain ? About how 
high above the Plain ? Locate Utah Lake. Do you 
think it is fresh or salt ? Why ? What is its outlet ? 
How would you infer the rainfall of the Plain from the 
drainage ? From the land forms ? 

Lake Bonneville once covered this plain to about the 
contour of 5200 feet. At this stage how far below the 
surface was the present site of Salt Lake City ? Along 
the Wasatch Mountains, what contrast between the land 
above and below the contour of 5200 feet ? At the 
mouths of many of the streams, especially Provo River 
and Spanish Fork Creek, are old deltas (compare Exer- 



258 MANUAL OF PHYSICAL GEOGRAPHY 

cise 127). What delta characteristics have they ? Find 
other examples. North of Stockton a bar was built. 
How long is it ? How high ? 

Why is irrigation of the eastern border of the Plain 
comparatively easy? What effect would the use for 
irrigation of water from the Wasatch Mountains have 
on the area of Great Salt Lake? Locate on the map 
the soil section shown in Figure 55. Why are stony 

soils found 

1 3 2 1 

1. STONY LOAM 2. GRAVELLY LOAM 3. LOAMS AND SANDY LOAMS Ileal U.lt3 IIIUUII- 

fig. 55. tains? Why is 

Soil Section from the Wasatch Mountains to the Oquirrh +V. prA nrniiplhi 
Mountains through the Mouth of the American Fork lIiere yravetiy 

canon, loam on the 

east side of the section and not on the west side ? 
Which soils were deposited in the deeper parts of Lake 
Bonneville ? Where are most of the towns in the Plain 
located ? Why ? 

References. — " Physiographic Regions," by J. W. Powell, 
" Physiography of the United States " ; Soil Surveys of the Provo, 
Utah, area (1903) and Goshen, Utah, area (1903). 

Plot the temperatures for Salt Lake City. How does 
your graph compare with New Orleans ? What is the 
monthly range ? Is the climate continental or oceanic ? 
Why? Plot the precipitation data. How does the 
graph compare with that for Bismarck ? Which place 
has the best arrangement of rainfall for crops ? 



STUDIES OF TYPICAL AREAS 
Salt Lake City 



259 





T. 


P. 


Snow 


R. H. 


January .... 


28° 


1.3 in. 


11.3 in. 


75 


February- 










33° 


1.4 in. 


10.8 in. 


70 


March . 










42° 


1.9 in. 


8.6 in. 


58 


April . 










50° 


2.1 in. 


2.5 in. 


48 


May . 










58° 


1.9 in. 


0.5 in. 


47 


June . 










67° 


0.7 in. 


T. 


38 


July . 










76° 


0.5 in. 


.Oin. 


34 


August 










75° 


0.8 in. 


.Oin. 


35 


September 








64° 


0.8 in. 


T. 


38 


October . 








52° 


1.5 in. 


1.0 in. 


51 


November 








40° 


1.5 in. 


5.8 in. 


62 


December 








33° 


1.4 in. 


9.7 in. 


71 


Year . . . 








52° 


15.8 in. 


50.2 in. 


52 


First killi 


]<>' 


fro 


3t i 


n 


autumn, ( 


)ctober 18. 







Last killing frost in spring, April 23. 

What is the length of the snow season ? How does 
it compare with that of New England ? Nashville ? 
What proportion of the precipitation is snow ? How 
does this snowfall affect the supply of water for the 
rivers flowing into the Great Basin from the east ? 

Would you describe the relative humidity as low or 
high ? How does it compare with New England ? 
What effect has this relative humidity on " sensible tem- 
peratures " ; e.g. how would the same temperature, 
warm or cold, feel in Utah and New England ? What 
effect does this relative humidity in Utah have on the 
supply of moisture for plants ? 



260 



MANUAL OF PHYSICAL GEOGRAPHY 



What is the length of the season free from frost? 
How does it compare with New England ? Nashville ? 



Average Hourly Temperatures for Salt Lake City and 
New Orleans 





Salt Lake 
City 


New- 
Orleans 




Salt Lake 
City 


New 
Orleans 


1 A.M. 


45.8 


65.4 


1 P.M. 


54.7 


71.6 


2 A.M. 


47.8 


65.0 


2 P.M. 


56.3 


72.3 


3 A.M. 


47.0 


64.6 


3 P.M. 


57.2 


72.7 


4 A.M. 


46.3 


64.2 


4 P.M. 


57.9 


72.9 


5 A.M. 


45.8 


63.9 


5 P.M. 


58.1 


72.7 


6 A.M. 


45.2 


63.6 


6 P.M. 


58.0 


72.0 


7 A.M. 


44.7 


63.6 


7 P.M. 


57.2 


70.7 


8 A.M. 


44.7 


64.3 


8 P.M. 


55.8 


69.2 


9 A.M. 


45.1 


65.5 


9 P.M. 


54.1 


68.1 


10 A.M. 


47.0 


67.3 


10 P.M. 


52.0 


67.3 


11 A.M. 


49.8 


69.1 


11 P.M. 


50.6 


66.5 


Noon 


52.5 


70.6 


Midnight 


49.4 


65.9 



Tampa? Plot the hourly temperatures for Salt Lake 
City and New Orleans. Which show the greatest range ? 
What, on the average, is the warmest hour at Salt Lake 
City ? At New Orleans ? What reason is there for 
this ? Which graphs show the steepest curves ? Which 
graph shows a continental daily range ? Which a 
marine daily range ? In this region much trouble is ex- 
perienced because " alkali " salts are drawn by capillary 
attraction to the surface of the soil and left there by evap- 
oration. How would the climate explain this process ? 



STUDIES OF TYPICAL ABEAS 261 

*198. THE PLATEAU OF ARIZONA AND THE GRAND 

CANON 

The following grouped maps : (Ariz.) St. George, 
Kanab, TJscalante, Henry Mountains, Mount Trumbull, 
Kaibdb, Echo Cliffs, Marsh Pass, Tusayan, San Francisco 
Mountains, Chino, Diamond Creek, Camp Mohave, (Nev.) 
Pioche, St. Thomas. 

Locate this region on a general map and shade the 
area included in the maps. Where does the Colorado 
River rise ? Into what does it flow ? What portion of 
the river is shown on these maps ? What length of the 
Colorado River is shown on these maps ? What is its 
general direction ? What is the altitude of the river 
east of Fremont River (northeast of Mount Holmes) ? 
What is its altitude north of Mount Newberry (near the 
Nevada-California line, southwestern part of map) ? 
What is the average fall per mile of the river ? Do you 
regard this as above or below the average for most 
rivers ? 

Beginning at the northeastern part of the map, trace 
the canon. Where does it become very deep? At this 
point does the land change in elevation ? How much ? 
Where does the deep canon end ? Does the land ele- 
vation fall here ? How much ? Locate the portion of 
the canon studied in Exercise 80. Of what two parts 
does it consist here ? Is this true of all parts of the 
canon ? 



262 



MANUAL OF PHYSICAL GEOGRAPHY 



Make a profile east and west along parallel 36° 30' 
and one north and south along the meridian of 112° 45' 
(follow method given in Exercise 190). 




Fig. 56. 
Generalized East-west Section across the Grand Canon Region. (After Dutton.) 

From Figure 56 determine the origin of each plateau. 
Which are bounded by faults ? Which by monoclines ? 
What is the origin of the Pink Cliffs (see Figure 57) ? 
The Vermilion Cliffs? How does a north-south section 

differ from an 

CO 

east-west section 
in structure? 
How in its topo- 
graphic types? 
Compare the 
Vermilion and 
the Pink cliffs 
with Echo Cliffs ; 
with the Cumberland escarpment ; the Niagara escarp- 
ment. 

Note the San Francisco Mountains. How far are 
they from the canon ? They are mostly rather recent 
volcanic cones and lava flows. The Uinkaret Mountains 




Fig. 57. 

Generalized North-south Section across the Grand 

Canon District. (After Dutton.) 



STUDIES OF TYPICAL AREAS 



263 



have a similar origin. How do the forms of these 
mountains suggest their origin ? Compare them with 
the Catskill Mountains (Exercise 83) ; the Blue Ridge 
(Exercise 88). 





Yuma, Arizona 
Altitude, 141 Ft. 


Flagstaff, Arizona 




T 


p. 


R H. 


T. 


p. 


Snow 


Jan. 


54° 


0.4 in. 


50 


26.7° 


2.00 in. 


14.5 in. 


Feb. 


59° 


0.5 in. 


49 


30.8° 


3.28 in. 


21.6 in. 


Mar. 


56° 


0.3 in. 


46 


35.9° 


1.81 in. 


12.4 in. 


April 


70° 


0.1 in. 


39 


42.2° 


1.63 in. 


6.6 in. 


May 


77° 


T. 


40 


50.7° 


1.21 in. 


5.3 in. 


June 


85° 


T. 


40 


59.3° 


0.55 in. 


0.5 in. 


July 


92° 


0.1 in. 


48 


65.0° 


1.79 in. 


.Oin. 


Aug. 


91° 


0.3 in. 


52 


62.8° 


3.30 in. 


.Oin. 


Sept. 


84° 


0.1 in. 


49 


55.5° 


2.00 in.- 


T. 


Oct. 


73° 


0.2 in. 


49 


44.7° 


1.89 in. 


0.7 in. 


Nov. 


62° 


0.3 in. 


47 


34.6° 


1.40 in. 


12.6 in. 


Dec. 


56° 


0.4 in. 


51 


28.4° 


1.95 in. 


7.1 in. 


Year 


72° 


2.7 in. 


46 


46.7° 


22.81 in. 


81.3 in. 



Mean annual pressure (1904) : Yuma, 29.74 in. ; Flagstaff, 23.37 in. 

Locate Yuma and Flagstaff. How far apart are they ? 
How do they differ in altitude ? How much farther 
north is Flagstaff ? 

How do their monthly and annual temperatures com- 
pare ? The snowfall ? The pressure ? How would you 
account for difference in annual pressure ? How much 
variation per hundred feet difference in altitude ? 



261 MANUAL OF PHYSICAL GEOGRAPHY 

Compare the monthly and annual rainfall. Plot the 
rainfall curve for Yuma. What maxima has it ? 
(This is characteristic of Arizona and New Mexico.) 
How would you account for the greater rainfall at 
Flagstaff ? Is this distribution of rainfall advantageous 
for most crops ? Why ? What two principal factors 
account for the difference in relative humidity at the 
two places ? 

Note the relative humidity at Yuma. What is its 
highest ? Invalids with lung troubles need a mild 
climate and dry air. Yuma is a winter resort, for such 
invalids. Why ? Why not a summer resort ? How 
does the relative humidity compare with New England ? 
Why is evaporation rapid in the plateau of Arizona and 
New Mexico ? How do native plants protect them- 
selves against this evaporation (see text-books on 
botany or an encyclopedia) ? 

*199. THE WESTERN GREAT BASIN AND THE SIERRAS 

The following grouped maps: (Nev.) Paradise, Dis- 
aster, Long Valley, [Col.) Alturas, Modoc Lava Bed, 
Shasta. 

Review Exercises 106 and 108. How much of the 
Shasta Quadrangle is covered by the Shasta Special 
Quadrangle ? What is the origin of Mount Shasta ? 
Where in this region are the Warner Mountains ? 



STUDIES OF TYPICAL ABEAS 265 

What is their origin ? What is the origin of Long 
Valley ? 

Locate this section on a general map and shade the 
area included in the maps. How long, east and west, 
is this section ? In the eastern part of the section are 
the " Basin Ranges." Name them. Where have 
you seen similar ranges ? About how high is the 
Plain ? In general how high above the Plain are the 
ranges ? In what direction do the ranges trend ? 
What can you infer as to the rainfall from the land 
forms ? By the drainage ? By the dune areas ? Why, 
in general, do the roads skirt the base of the ranges ? 
These ranges are sometimes called " buried ranges ' ; 
(see the text-books in physical geography or geology). 
Why? 

West of the buried ranges is a lava plateau. How 
does its topography compare with that of the Plain ? 
How would you describe the dissection of this plateau ? 

Locate the Sacramento River. Into what does it flow ? 
Trace the divide between this river and the Great 
Basin drainage. What is its altitude? Is it a sharply 
defined divide ? How does it compare in this respect 
with the divides on the Coastal Plain ? With those in 
the Appalachian Ridges ? In the Cumberland Plateau ? 

Compare the streams on each side of the Pacific- 
Great Basin divide ; the dissection. Account for the 
contrasts. 



266 MANUAL OF PHYSICAL GEOGEAPHY 

How far is Mount Shasta from the Pacific? The 
complex mountains in the vicinity of Mount Shasta 
belong to a group that is sometimes called the Klamath 
Mountains. What is their average height ? What is 
the average depth of valleys ? 

Noting the drainage across this area, what can you 
tell of the rainfall ? How would you explain its distri- 
bution ? 

*200. THE SIERRAS IN CALIFORNIA 

The following grouped maps: (Cal.) Chico, Bidwell 
Bar, Doivnieville, Sierraville, Truckee, Colfax, Smarts- 
ville, Marysville, (Nev.) Reno, Wadsivorth, Wabuska, 
Carson. 

Locate this region on a general map and shade the 
area included. How far south is it from the area 
treated in Exercise 199? What is the length of this 
section ? Review Exercises 109 and 140. 

Trace the eastern border of the Sierra Nevada Moun- 
tains. In what direction is their trend? How high is 
it above sea level ? Above the general altitude of the 
Great Basin ? Where is its slope steepest ? Where least 
steep ? How does the Great Basin topography compare 
with that in the Warner Mountain region? With that in 
the Utah region ? What lakes are there in the Great 
Basin ? How and into what is Lake Tahoe drained ? 
What undrained lakes ? What basins not now occupied 
by water ? 



STUDIES OF TYPICAL AREAS 267 

How wide is the belt of Sierras here ? What is its 
general height ? In which direction do most of the 
streams flow ? In what part is the Pacific-Great 
Basin divide ? What are the principal streams ? 
Which does the topography most resemble, that of the 
Appalachian Ridge Belt or the Alleghany-Cumberland 
Plateau ? What predominant stream pattern ? Where 
has there been glaciation ? Do you think it was of the 
mountain or the continental type ? Give full reasons 
for your opinion. 

Compare the eastern and western margins of the 
Sierras in height, dissection, steepness. Which is for 
the most part an escarpment ? One of these edges is 
for the most part a recent fault scarp. Which do you 
think is the fault scarp ? Why ? Which direction has 
the block including the Sierras evidently been tilted ? 
How do you know ? 

What is the altitude of the Sacramento Valley ? 
How do this valley and its river compare with the 
same valley and river noted in Exercise 199 ? How 
would you describe the surface of the valley ? What 
natural facilities for irrigation in the valley ? 

Trace the Central Pacific Railroad. What physio- 
graphic features does it use ? The old California trail 
followed the Truckee River to the Donner Pass and 
thence down the American or Bear River to the Sacra- 
mento Valley. Where is the highest point on the trail ? 



268 



MANUAL OF PHYSICAL GEOGRAPHY 



How does this pass compare with the Cumberland 
Gap? 

Which division, the Great Basin, the Sierras, or the 
valley of the Sacramento, offers the best soils ? How 
would you account for the number of towns in the 
Sierras ? 

Keferences. — The following folios, U.S.G.S., Marysville, 
Smartsville, Colfax, Truckee. 





Chico, Cal. 


Donner, Cal. 


Carson City, 


Nev. 




T. 


P. 


T. 


P. 


Snow 


T. 


P. 


Snow 


Jan. 


47° 


4.5 in. 


28° 


8.2 in. 


79 in. 


33° 


2.0 in. 


8.3 in. 


Feb. 


50° 


3.3 in. 


29° 


7.0 in. 


74 in. 


36° 


1.6 in. 


10.2 in. 


Mar. 


56° 


2.7 in. 


31° 


8.0 in. 


84 in. 


41° 


1.3 in. 


7.5 in. 


April 


62° 


1.8 in. 


36° 


5.2 in. 


55 in. 


47° 


0.6 in 


2.2 in. 


May 


68° 


1.0 in. 


43° 


2.1 in. 


20 in. 


54° 


0.8 in. 


0.4 in. 


June 


77° 


0.4 in. 


53° 


0.6 in. 


2 in. 


61° 


0.3 in. 


T. 


July 


84° 


T. 


61° 


0.2 in. 


in. 


68° 


0.1 in. 


in. 


Aug. 


82° 


T. 


60° 


0.5 in. 


Oin. 


67° 


0.3 in. 


in. 


Sept. 


75° 


0.5 in. 


54° 


0.2 in. 


2 in. 


60° 


0.3 in. 


0.0 in. 


Oct. 


65° 


1.4 in. 


44° 


2.5 in. 


14 in. 


50° 


0.5 in. 


0.9 in. 


Nov. 


54° 


2.6 in. 


36° 


4.5 in. 


35 in. 


42° 


1.3 in. 


1.5 in. 


Dec. 


48° 


4.2 in. 


30° 


7.9 in. 


68 in. 


34° 


1.7 in. 


5.0 in. 


Year 


64° 


22.4 in. 


42° 


46.9 in. 


433 in. 


49° 


10.8 in. 


36.0 in. 



First killing frost in autumn : Chico, December 14 ; Carson City, 
September 20. 

Last killing frost in spring : Chico, March 24 ; Carson City, May 20. 

Locate Chico, Donner (near Donner Lake on the 
Central Pacific Railroad), and Carson City. In what 
physiographic divisions are they located? What are 
their altitudes ? 



STUDIES OF TYPICAL ABE AS 269 

Plot the temperatures for these places. What are 
the monthly temperature ranges ? In what months 
does the maximum come ? The minimum ? Account 
for the differences in temperature between Chico and 
Donner ; between Chico and Carson City ; between 
Donner and Carson City. 

Plot the precipitations for these places. Are the 
graphs parallel ? Which are most nearly parallel ? 
When does the maximum precipitation come ? The 
minimum ? This arrangement of precipitation is called 
the " Pacific Type." How would you describe the 
type ? How does this compare with the precipitation 
of Bismarck, Nashville, and Tampa ? 

How would you explain the difference in precipita- 
tion between Chico and Donner ? What percentage 
falls during the crop-growing season ? What are the 
snow months at Donner ? At Carson City ? What is 
the length of the snow season at these places ? Give 
at least two reasons for your answer. What percent- 
age of the total precipitation at these places is snow ? 
What advantage to the people in the Sacramento Val- 
ley has the snowfall in the mountains ? 

The snowshed system of the Southern Pacific Rail- 
road extends from Blue Canon to Truckee. What is 
its length ? Compare the temperatures of the three re- 
gions for wheat growing. For fruit. Why is irriga- 
tion desirable in this part of California, which has a 



270 



MANUAL OF PHYSICAL GEOGRAPHY 



rainfall of over twenty inches ? From the frost dates, 
what region would you think favorable for fruit grow- 
ing ? Much wheat is grown in the Valley of California. 
What climatic factors favor this crop ? 

Note. — Summit, Cal., near Dormer, is the station from which the 
data for Donner is given. Summit is not shown on the map. 

California is a state with many varieties of climate. 
The section given above is in what part of the state ? 
In what part of the state is the map in Exercise 60 
located ? Along the alluvial fans are some of the most 
extensive vineyards of raisin grapes in the country. 
How does the raisin grape differ from other grapes ? 
It needs a warm climate, sunshine, and a rainless sea- 
son for drying. How do the following data at Los 
Angeles fit these requirements ? 





Los Angeles 


Independence 




T. 


P. 


R. H, 


Sun- 
shine 1 


T. 


P. 


R. H. 


Sun- 
shine 1 


Winter 


55 


8.9 in 


65 


74 


43 


2.0 in. 


41 


72 


Spring 


60 


4.3 in. 


73 


66 


56 


0.6 in. 


27 


82 


Summer 


70 


0.1 in. 


75 


74 


76 


0.2 in. 


20 


89 


Autumn 


65 


2.3 in. 


70 


77 


60 


0.9 in. 


28 


85 


Year 


62 


15.6 in. 


71 


73 


59 


3.7 in. 


29 


82 



Percentage of possible sunshine. 



The grapes are often taken to the "desert" to dry. 
Independence is located on the western edge of this 



STUDIES OF TYPICAL AREAS 271 

" desert." Locate it on a map of the state. How does 
the sunshine of Independence compare with that of 
New Orleans ? Which has the more cloudy weather ? 
Which the greater relative humidity ? What fac- 
tors in the desert promote raisin making ? Are these 
factors favorable for crops ? Which of the two sta- 
tions, Los Angeles or Independence, have continental 
climates ? How do you know ? Wliich marine ? Why ? 

201. THE NORTHERN CASCADE MOUNTAINS AND THE 
COLUMBIA PLATEAU 

The following grouped maps: (Wash.) Glacier Peak, 
Stehekin, Methoiv, Okanogan, Chelan, Chiwankum, Sky- 
komish. 

Shade this area on a general map. In what part of 
the state is the area located ? In what direction from 
Seattle ? How far and in what direction is this area 
from those shown in Exercises 199 and 200 ? 

On a general map trace the Columbia River. What 
part of this river is shown in this map? Trace on a 
general map the Cascade Range. What portion is 
shown in this map? What is the general altitude of 
the peaks of this range? What is the general alti- 
tude of the Columbia Plateau? What difference in 
altitude between the two divisions ? 

Note and locate the glaciers. What is the general 
lower limit of glaciation ? How does this compare 



272 MANUAL OF PHYSICAL GEOGRAPHY 

with Mount Shasta? Do you find the same distribu- 
tion of glaciers as on Mount Shasta ? In general, how 
are the glaciers in this region distributed with respect 
to the divide ? How will the following table for a 
station in this vicinity explain this distribution ? (Ex- 
plain fully.) 

Average Number of Winds prom Different Directions 
at Portland, Ore. (1891-1895) 

N. . . . 1498 S. . . . 1835 

N.E. . . 454 S.W. . . 1083 

E. . . . 310 W. . . 283 

S.E. . . 1033 N.W. . 2076 

Do you think that this topography is due mainly to 
glacial or to subaerial erosion ? What features are 
plainly of glacial origin ? What features are largely 
due to subaerial erosion? How does the region com- 
pare with the Mount Washington district ? With the 
Gilbert Peak district? With the Mount Mitchell dis- 
trict ? Compare the surface of the Columbia Plateau 
with that of the Cascade Range. 

Trace the Stehekin River. Is there any peculiarity ? 
How long is Lake Chelan ? What average width ? 
How far, on the average, is it below the uplands ? How 
would you describe the valley sides ? How do these 
compare with those of Cayuga Lake (Exercise 127)? 
Trace the divide on either side of Lake Chelan. How 



STUDIES OF TYPICAL AREAS 273 

far on the average is the divide west of the lake ? 
East of the lake ? Is this usual ? Why ? 

What glacial features on either side of Sawtooth 
Ridge? Find other examples. 



APPENDIX 

Apparatus. — Cross-section paper should have about ten 
squares to the inch. Blank maps of the United States will 
be needed in the areal studies. 

Ex. 2. — Any device will do that will give a horizontal 
wire that can be revolved about an axis. A ring stand from 
the chemical laboratory with a wire fastened to the ring will 
do fairly well. The Central Scientific Supply Co., 14 Michi- 
gan Street, Chicago, will furnish the apparatus for |1.00. 

Ex. 3. — Compass and globe can be procured from dealers 
in apparatus. 

Ex. 9. — Goode's Sun Board can be procured from the 
Central Scientific Supply Co. (see above), price $12.00. 

Daily weather maps can be procured on application to the 
nearest station. Usually half a dozen or more daily maps 
will be sent to teachers for use in the classroom. It is a 
good plan to select good type maps and preserve them for 
reference. In this way a valuable working collection will 
soon be formed. Blank weather maps (form DD) can be 
ordered from the Weather Bureau for about 20, cents per 
hundred. 

Rocks and minerals may be obtained from the following 
firms : Foote Mineral Co., 107 North 9th St., Philadelphia, 
Pa. ; Ward's Natural Science Establishment, 16 College Ave., 
Rochester, N.Y. ; Central Scientific Co., 14 Michigan St., 

Chicago, 111. 

. 275 



276 MANUAL OF PHYSICAL GEOGRAPHY 

If the teacher is in a glaciated region, usually specimens 
of most of the rocks called for can be found. The local 
granite dealer can often supply most of them. It should be 
remembered that the term " granite " in. trade is usually ap- 
plied to almost any igneous rock. Often the teacher can ob- 
tain a good collection by exchanging local material. There 
are few localities that cannot furnish interesting material. 

Charts. — All purchases from the government bureaus 
should be accompanied by remittances, either in cash or 
money order. Mississippi River charts are published in two 
scales: one of one mile to the inch, price 10 cents; and the 
other of three miles to the inch, price 26 cents. Remittances 
should be sent to the Mississippi River Commission, St. 
Louis, Mo. 

Coast charts are issued by the U. S. Coast and Geodetic 
Survey, Washington, D.C., where orders should be sent. 
This Survey sends free a catalogue of its charts. 

Coast Charts. — 314, Kennebec and Sheepscot Rivers (25 
cents); 315, Casco Bay (25 cents); (both for reference); 
*1007, Gulf of Mexico (50 cents); *5300, Santa Rosa Island 
to Point Buchon (50 cents); *120, New York Bay and Harbor 
(50 cents); *152, Newfoundland Harbor to Boca Grande Key 
(50 cents); *5532, San Francisco Entrance (50 cents); *121, 
Sandy Hook to Barnegat Inlet (50 cents); *110, Cape Cod 
Bay (50 cents) ; 123, Absecon Inlet to Cape May (50 cents) ; 
359, Thames River and Harbor of New London (40 cents); 
*337, Boston Harbor (50 cents) ; 5100, San Diego to Santa 
Monica (50 cents); *194, Mississippi River from the Passes 
to Grand Prairie (50 cents) ; *195, Mississippi from Grand 
Prairie to New Orleans (50 cents) ; *204, Galveston Bay 
(50 cents); *5500, Pacific Coast from Point Pinos to Bodega 
Head (50 cents); *469, Key West Harbor (25 cents); 244, 
Salem Harbor (25 cents). 



APPENDIX 277 

Charts of the Hjdrographic Office, Navy Department, 
Washington, D.C. 

1850, Port Apra, Guam (60 cents) ; 1802, Funafuti Atoll 
(60 cents). 

Pilot charts of the North Atlantic Ocean, price 10 cents. 
Often canceled or unused charts will be sent free to schools. 

Charts of the Lake Survey, War Department, *No„ 2, 
Lake Ontario, *No. 3, Lake Erie (15 cents each). Remit- 
tances should be made by money order payable to the order 
of U. S. Lake Survey Office, at the Old Custom House, 
Detroit, Mich., or to the order of U. S. Engineer Office, at 
Federal Building, Buffalo, N.Y. 

" Tide tahles" price 50 cents, gives much interesting infor- 
mation from stations in different parts of the earth. Data 
may be found for the Atlantic coast in " Tide Tables for 
the Atlantic Coast " (15 cents), and for the Pacific coast in 
" Tide Tables for the Pacific Coast " (10 cents). Order 
from the U. S. Coast and Geodetic Survey. 

Reports of the U. S. Soil Survey are not on sale, but may 
often be obtained from your congressman. These reports 
contain much valuable geographic material. 

Folios issued by the U. S. Geological Survey are recom- 
mended as follows (the price is 25 cents each, except the 
New York City Folio, which is 50 cents) : Absaroka, Wyo. ; 
*Telluride, Col. ; *Ellensburg, Wash.; * Fargo, N.D.; Mt. 
Mitchell, N.C.-Tenn. ; Kingston, Tenn. ; Pikeville, Tenn.; 
McMinnville, Tenn.; Marysville, Cal.; Smartsville, Cal. ; 
Colfax, Cal.; Truckee, Cal.; *New York City,N.Y.; Green- 
ville, Tenn.; Holyoke, Mass; (any one of the following will 
be sufficient for Ex. 191) Edgemont, S.D.-Neb.; Oelrichs, 
S.D.-Neb.; Newcastle, Wyo.; Sundance, Wyo. 

Books. — No extended bibliography has been included in 
the Manual. As a rule, references are given only to those 



278 MANUAL OF PHYSICAL GEOGRAPHY 

books that pertain to the area under discussion. Books 
published by the U. S. Geological Survey are indicated thus: 
U.S.G.S. Of course, the school library should include 
the various text-books, especially if the topical method is 
followed. Reports of the U. S. Geological Survey that are 
out of print are not included in this list. Climate, Ward, 
Putnam (12.00); Physical Geography of New York, Tarr, 
Macmillan Co. (13.50); Geographic Influences in American 
History, Brigham, Ginn & Co. ($1.25); American History 
and Its Geographic Conditions, Semple, Houghton Mifflin 
Co. ($3.00); Cumberland Road, Hulbert, A. H. Clark 
($2.50); Physiography of the United States, American Book 
Co. ($1.50), U.S.G.S.; Monograph 41, Drainage Features of 
the Erie and Ohio Basins, by Frank Leverett ($1.75); Mono- 
graph 25, The Glacial Lake Agassiz, by Warren Upham 
($1.70) ; Professional Paper No. 34, The Delavan Lobe of the 
Lake Michigan Glacier, by Wm. C. Alden (a limited number 
are for free distribution); Professional Paper No. 40, The 
Interpretation of Topographic Maps, by R. D. Salisbury and 
W. A. Atwood, is valuable and will be sent free to teachers. 
Topographic Maps Needed in the Text. — Those maps needed 
for the suggested briefer course are starred (*). A few 
maps useful for reference are indicated by the word refer- 
ence. They should be ordered from the U. S. Geological 
Survey, Washington, D.C. Unless otherwise stated, the 
price is 3 cents per map if 100 or more maps are ordered. 
For orders for less than 100 maps the price is 5 cents each. 
Ala. : Gadsden. 
Alaska: *Nome Special. 
*Ark.: Marshall. 

Ariz. : *Bright Angel, (5 cents) *Mt. Trumbull. 
Cal. : *Alturas, Corona, *Cucamonga, *Marysville,*San Luis, 
*Shasta Special (5 cents), Sierraville, *Temalpais. 



APPENDIX 279 

Col. : *Telluride, Denver (5 cents). 

Conn. : *Hartford, New London. 

Fla. : *Arredono, Dunnellon (reference). 

Ga. : *Marietta. 

la. : *Anamosa. 

111. : High wood, Peoria. 

Kan. : * Caldwell, Abilene. 

La. : Bayou Sara, *Donaldsonville, East Delta, *New Orleans, 
West Delta. 

Me. : Bath, *Boothbay. 

Md. : Frostburg, *Grantsville, *Pawpaw. 

Mass. : Abington, *Boston, *Boston Bay, Holyoke, Plymouth, 
*Provincetown, *Wellneet. 

Minn. : *St, Paul. 

Neb.: ^Lexington. 

Nev. : *Long Valley. 

N. J. : * Atlantic City, *Navesink, *Raritan, Passaic, Sandy- 
hook, Trenton. 

N.Y. : Elmira, Harlem, *Islip, *Kaaterskill, *Lockport, *Mt. 
Marcy, ^Niagara Falls, Palmyra, * Rochester, Watkins, 
Watkins Glen (supplementary). 

N. C. : Mt. Mitchell. 

N.D.: *Fargo. 

Ohio: *Berea, *Mt. Sterling. 

Ore.: Crater Lake Special (5 cents). 

Pa.: Carnegie (reference), *Chester, Germantown, *Harris- 
burg, Huntington, *New Bloomfield, Norristown, * Pitts- 
burg, *Waynesburg. 

S.D.: *Elk Point. . 

Tenn.: Briceville, Cumberland Gap (reference), Greenville, 
Kingston, McMinnville, Nashville (reference), *Pikeville. 

Tex. : *Austin. 

Utah: Henry Mts., *Gilbert Peak, Manti. 



280 



MANUAL OF PHYSICAL GEOGRAPHY 



Va. : *Harper's Ferry, *Hampton, *Staunton, Richmond. 
Wash. : *Ellensburg. 

W.Va. : Buckhannon, Charleston, Guyandot, New Martins- 
ville. 
Wis.: *Eagle, *Lancasteiy *Portage, *Sun Prairie, * White- 
water. 
Wyo. : *Tshawooa. 

Mounting Maps. — In the long run, it is economical to 
mount single sheets. Thin white cotton cloth should be used 
for the backing. Stretch the cloth on a smooth surface, such 
as a drawing board or a table top, and thoroughly wet the 
cloth. A very smooth floor will do for the grouped sheets. 
It should, of course, first be made thoroughly clean. Thor- 
oughly cover the back of the sheet with flour paste, which 
can usually be obtained from a paper hanger, and lay the sheet 
smoothly upon the cloth. Carefully press the map to the 
cloth with a piece of clean cloth or a photograph roller. 

Grouped sheets must first be trimmed, leaving the im- 
printed edges of alternate maps projecting about one fourth of 
an inch. For example, to trim the 
nine maps shown in Figure 58, trim 
1, 2, and 3 with ^ inch of unprinted 
paper at the top so that 4, 5, and 6 
may be lapped over them. Trim 1 
and 2 with \ inch projecting at the 
right, so that they may be lapped over 
on the sides ; likewise, trim 4 and 5 
with the projection on left sides. In 
this way, the overlaps are alternate, and the map is not so 
likely to break along the line of laps. The trimming may 
be done with shears or with a sharp knife. 

Common causes of failure are due to "blisters." The paper 
in drying separates from the cloth and is soon worn or torn. 



9 


i 
i 

I 8 

i 

4 — T . 




7 


6 j 

j. 


5 

-T -4- 


4 


1 


2 


i 
i 

! 3 

I 

1 



Fig. 58. 



APPENDIX 281 

This is usually due to air bubbles beneath the paper or cloth, 
lack of paste, or insufficient or uneven wetting of the cloth. 
Sometimes the maps crack. This is often clue to rough han- 
dling or too much paste. If the edges of the maps are not 
thoroughly pasted and pressed down, they may roll up. Un- 
less one is very expert, the maps should be fitted as trimmed. 
At least a day is usually required for drying. 

Grouped maps should be rolled upon straight, well-sea- 
soned curtain poles. Hanging rings may be screwed into the 
poles, or cloth loops can be nailed to them. After use, the 
maps should be carefully rolled and put away, preferably on 
brackets or shelves. 

exercise Mounted Maps 

128. (Minn.) Minneapolis, St. Paul, White Bear, Anoka. 

*185. (N.D.) Fargo, Casselton, Tower. 

*186. (Kan.) Caldwell, Cheney, Kingman, Anthony. 

*187. (N.Y.) Sodus Bay, Oswego, Fulton, Mexico, Syracuse, 
Baldwinsville, Weedsport, Clyde, Geneva, Auburn, 
Skaneateles, Tully, Cortland, Moravia, Genoa, Ovid, 
Watkins, Ithaca, Dry den, Hartford, Apalachin, 
Oswego, Waverly, Elmira. 

*188. Trenton, N.J. -Pa., Navesink, N.J.-N.Y., Passaic, 
N.J.-N.Y., and Raritan, N.J. 
189. (Md.) Green Run, Ocean City, Pittsville, Snow Hill, 
Princess Anne, Salisbury, Nanticoke, Deal Island, 
Crapo, Oxford, Bloodsworth Island, Sharps Island, 
Drum Point, Point Lookout, Prince Frederick, 
Leonardtown, Piney Point, Montross, Wicomico, 
Brandywine. 
(Va.) Fredericksburg, Mt. Vernon, Harper's Ferry, 
Warrenton, Spottsylvania, Gordonsville, Luray, 
Winchester. 



282 MANUAL OF PHYSICAL GEOGRAPHY 

Exercise 

(Va.) Harrisonburg, Staunton, (W. Va.) Franklin, 
Piedmont, St. George, Beverley, Monterey, Buck- 
hannon, Huntersville, Nicholas, Sutton, Romney, 
Woodstock. 

*190. (N.C.) Yadkinville, Statesville, Hickory, Wilkesboro, 
Cranberry, Morgantown, Roan Mt., Mt. Mitchell, 
Saluda, Pisgah, Asheville, (Tenn.) Greenville, 
Morristown, Mt. Guyot, (N.C.) Cowee, Nahantala, 
(Tenn.) Knoxville, Maynardsville, Briceville, 
Loudon, Murphy, Cleveland, Kingston, Wartburg, 
Standingstone, Pikeville, Chattanooga, Sewanee, 
McMinnville. 

*191. (Pa.) Sunbury, Shamokin, Catawissa, Pine Grove, 
Lykens, Millersburg, Millerstown, New Bloomtield, 
Harrisburg, Hummelstown, Lebanon. 

192. (Fla.) Williston, Citra, Dunnellon, Ocala, Tsala 
Apopka, Panasoffkee. 

*194. (Conn.) Putnam, Moosup, Stonington, New London, 
Norwich, "Woodstock, Toland, Gilead, Saybrook, 
Guilford, Middletown, Hartford, Granby, Meriden, 
New Haven, Winsted, Waterbury, Derby, Bridge- 
port, Norwalk, Danbury, New Milford, Cornwall, 
(N.Y.-Conn.) Middlebrook, Clove, Carmel, (N. Y.) 
Stamford. 

195. (S.D.) Rapid, Hermosa, Oelrichs, Edgemont, Harney 
Peak, Dead wood, (Wyo.) Sundance, Newcastle. 

*196. (Col.) Pikes Peak, Colorado Springs, Big Springs, 
Canon City, Pueblo, Nepesta, Huerfano Park, 
Walsenburg, Apishapa. 

*197. (Utah) Ashley, Uinta, Salt Lake, Toole Valley, 
Sevier Desert, Manti, Price River, East Tavaputs. 

*198. (Nev.) Pioche, (Ariz.) St. George, Kanab, Escalante, 
Henry Mts., (Nev.) St. Thomas, (Ariz.) Mt. Truni- 



APPENDIX 283 

Exercise 

bull, Kaibab, Echo Cliffs, Marsh Pass, Tusayan, 
San Francisco Mt., Chino, Diamond Creek, Camp 
Mohave. 

*199. (Nev.) Paradise, Disaster, Long Valley. 
(Cal.) Alturas, Modoc Lava Bed, Shasta. 

^200. (Cal.) Chico, Bid well Bar, Downieville, Sierraville, 
Truckee, Colfax, Smartsville, Marysville, (Nev.) 
Reno, Wadsworth, Wabuska, Carson. 

201. (Wash.) Glacier Peak, Stehekin, Methow, Okanogan, 
Chelan, Chiwankum, Skykomish. 



INDEX 



Absaroka Mountains, Wyo., 120. 

Adirondacks, 157. 

Adjusted streams, 133. 

Agassiz, Lake, 92, 220. 

Age, region in, 99, 100. 

Alkali Lake, Cal., 175. 

Alleghany FroDt, 236; section of, 235. 

Alleghany Plateau, 196; in N.Y., 224; 
in W. Va.,236. 

Allegrippis Ridge, Pa., 135. 

Alluvial fans, 82, 81 ; compound or pied- 
mont, 83. 

American Fork Canon, Utab, 258. 

Anticline, eroded, 124 ; pitching, 130. 

Anticyclones, conditions in different 
parts of, 38; inference from iso- 
therms, 37; inference from wind 
directions, 36 ; isotherms in, 35 ; in 
summer and winter, 41; map study 
of, 29. 

Apia (Samoan Islands), tides at, 181. 

Apra, harbor of, 209. 

Arizona Plateau, 261. 

Asheville, N.C., monthly temperature 
at, 241. 

Atlanta, Ga., monthly temperature and 
precipitation at, 241. 

Atlantic, depths of, 177. 

Atlantic City, N.J., 191. 

Atoll, 184. 

Ausable Lakes, N.Y., 171. 

Axis, earth's, inclination of, 3. 

Azores, 177. 

Babylon, N.Y., 155. 

Back River, Va., 106. 

Backbone Mountain, W. Va., 236. 

Balcones, Tex., 144. 

Bars, off-shore, 189; river, 85. 



Basalt, 57. 

Base level, 71. 

Bath, Me., harbor, 210; tide at, 181. 

Bear River, Cal., 267. 

Beaverdam Creek, Va., 134. 

Big Sioux River, Neb., 80. 

Bismarck, N.D., average hourly tem- 
perature at, 17; climate at, 221. 

Black Hills, 252; artesian water from, 
254 ; rainfall at, 255 ; section of, 253. 

Black Mountains, N.C., 118. 

Black Oak Ridge, Tenn., 136. 

Blue Canon, Cal., 269. 

Blue Mountain, Pa., 127, 136. 

Blue Ridge in Md. and Va., 234; in 
N.C., 119, 158, 237; in Va., 134. 

Boston, Mass., harbor, 206; land and 
sea breeze at, 43 ; tides at, 179, 181. 

Boston Mountains, Ark., 115. 

Bowman Creek, N.Y., 111. 

Breckinridge, Col., monthly tempera- 
tures at, 19. 

Breeze, land and sea, at Boston, 43. 

Brigantine beach, N.J., 189. 

Brigham, A. P., cited, 237. 

Buckhannon River, W. Va., 90. 

Buried ranges, 265. 

California trail, 267. 
Campbell, M. B., cited, 137. 
Canary Islands, lagging of tides at, 181. 
Caney Fork, Tenn., 114. 
Canoe Valley, Pa., 130. 
Canon, study of a, 109. 
Capacity of the atmosphere, 20. 
Cape Canaveral, 178. 
Cape Cod, 200. 

Carson City, Nev., temperature, precipi- 
tation and snow at, 268. 



285 



286 



INDEX 



Cascade Mountains in Wash., 271. 

Catharine Creel?, N.Y., 163. 

Catskill Mountains, N.Y., 114. 

Chaptico Bay, Md., 234. 

Chattahoochee River, Ga., 100. 

Chattanooga, Tenn., 239; in the Civil 
War, 243. 

Chemung River, N.Y., 96. 

Cherrapunji, India, monthly rainfall at, 
27. 

Chesapeake Bay, shore of, 233. 

Chestnut Ridge, O., 196. 

Chico, Cal., temperature and precipita- 
tion at, 268. 

Chinook wind at Denver, Col., 44. 

Christiania, Norway, monthly tempera- 
tures at, 15. 

Cinder cones, 150. 

Circle, great, 5. 

Circle of illumination, 5. 

Cirques, 120, 152. 

Cleavage forms, 55. 

Cleavage of minerals, 54. 

Cliffs, wave-cut, 198. 

Clinometer, 70. 

Clouds, study of, 47. 

Coast, young, 188 ; risen, 197. 

Coastal Plain in Fla., 246; in N.J., 
198; in Md. and Va., 233; narrow, 
198. 

Cold wave, 41. 

Colorado Canon, 109. 

Colorado Plateau, Ariz., 257. 

Colorado River, Ariz., 109, 261; valley, 
Tex., 144. 

Columbia Plateau, Wash., 271. 

Columbia River, Wash., 271. 

Conglomerate, 56. 

Connecticut River, 249 ; terraces of, 87 ; 
soils along, 216. 

Conodoguinet Creek, Pa., 137, 245. 

Consequent streams, field study of, 106; 
map study of, 107 ; lakes, 173. 

Continental shelf, 178. 

Coral reefs, 185. 

Corrasion curves, 72. 

Cotton, climatic conditions of, 242. 

Cove Creek, Pa., 130. 

Crab Orchard Mountains, Tenn., 124. 

Crater Lake, Oregon, 173. 



Crawford Mountain, structure of, 126. 

Crystal form, 55. 

Cuba, reefs on, 185. 

Cuesta, 141. 

Cumberland Gap, Tenn., 241. 

Cumberland Plateau, Tenn., 240. 

Cumberland River, Tenn., 242. 

Currents, shore, 192. 

Cut-offs, river, 86. 

Cyclones, conditions in different parts, 

38; inference from isotherms, 37; 

inference from wind directions, 36; 

isotherms in, 35; map study of, 28; 

paths, 42; in summer and in winter, 

41. 

Dakota sandstone, 140. 

Damariscotta River, Me., 159. 

Dana Butte, Ariz., 110. 

Dartou, N. H., cited, 254. 

Davis, W. M., cited, 251. 

Day and night, length of, 5. 

Daylight, duration at various latitudes, 
7; at60°N., 15. 

Dead River, Fla., 246. 

DebowHill, N.J., 141. 

Delaware and Raritan Canal, 230. 

Delta, hanging, 164; Mississippi, 80; in 
Seneca Lake, N.Y., 165; tidal, 199. 

Dendritic stream pattern, 107. 

Denver, Col., 44,140. 

Desplaines River, 111., 93. 

Dew-point, ascertainment of, 46 ; obser- 
vations of, 46. 

Dike, 150. 

Diller, J. S., cited, 148. 

Diorite, 57. 

Dip and outcrop, 135. 

Divide, mountainous, 118. 

Dodge City, Kan., hot wind at, 224. 

Donner, Cal., temperature, precipita- 
tion, and snowfall at, 268. 

Donner Pass, Cal., 267. 

Drowned stream valleys, 105. 

Drumlins, 161 ; soils on, 218. 

Earth, form of, 1; monthly distances 
from the sun, 10 ; average daily ve- 
locities, 11 ; path, 11. 



INDEX 



287 



Egg Harbor Inlet, N.J., 191. 

Elbow of capture, 90. 

Erie Canal, 227. 

Erosion, headwater, 94; subaerial and 

glacial, 158. 
Escarpment, Niagara, 116; Tenn., 117. 

Fall line, 229 ; in Va., 234. 

False River, La., 86. 

Fault block, 199. 

Fault scarp in Cal., 145, 267; dissected, 
143. 

Faulted structure, 146. 

Feather River Valley, Cal., 176. 

Finger Lakes, N.Y., 225. 

Fiords, 158. 

Fishing Creek, Pa., 108, 132. 

Flagstaff, Ariz., temperature, precipi- 
tation, and snow at, 263. 

Flood plains, 78. 

Florida, 175. 

Fog, study of, 47 ; in the Atlantic, 51. 

Folded structure, erosion forms on, 
146; stage of erosion on, 138. 

Forecasting, local, 50. 

Fort Snelling, 166. 

Fox River, Wis., 167. 

French Broad River, N.C., 238. 

Frost conditions, map study of, 49; 
observations of, 48. 

Funafuti Island, 184. 

Gainesville, Fla., soils near, 218. 

Galveston, Tex., harbor, 207. 

Genesee River, N.Y., 160. 

Gilbert, C. K., cited, 116. 

Gilbert Peak, Utah, 158. 

Glacial deposition, 162. 

Glaciation, 157. 

Glaciers, Alpine, 152. 

Gneiss, 57. 

Golden Gate, Cal., 200. 

Goodwin Islands, Va., 106. 

Governor's Island, N.Y., tides at, 182. 

Gradient, temperature, 38; barometric, 

32. 
Grand Canon, Ariz., 261. 
Granite, 57. 

Grant's Memoirs, cited, 244. 
Graph, 1. 



Great Bahama Island, reefs on, 185. 
Great Basin, in Utah, 256; western part 

of, 264. 
Great Plains, 139, 252 ; in Colorado, 255 ; 

precipitation of, 222. 
Great Valley, in Md., W. Va., and Va., 

235; in Pa., 244; in Tenn., 239. 
Ground water, 71. 
Gulf Stream, 183. 
Guyandot River, W. Va., 101. 

Half Falls Mountain, Pa., 132. 

Harbors, 203, atoll, 211 ; bar, 206 ; coral 
reef, 209; drowned valley, 204 ; fiord, 
210; hook, 211; moraine, 206; rias, 
208; river, 205; spit, 211; tied island, 
212. 

Hardness of minerals, 54. 

Harper's Ferry, 135. 

Harrisburg, Pa., 137. 

Hayes, C. W., cited, 101, 119. 

Henry Mountains, Utah, 149. 

Hickory Ridge, Pa., 132. 

Highland Rim, Tenn., 240. 

Highlands of New Jersey, 228. 

Hills, 113. 

Hog backs, 139, 254, 256. 

Holyoke Range, Mass., 138. 

Honolulu, tides at, 181, 183. 

Hook, 193. 

Hoop Pole Ridge, W. Va., 236. 

Hotlum glacier, Cal., 152. 

Housatonic River, Conn., 250. 

Hudson, old channel of, 193. 

Hulbert, A. B., cited, 242. 

Humidity, absolute, continental and 
marine, 24. 

Humidity, relative, table, 21 ; diurnal, 
23; continental and marine, 24. 

Hurricane Ledge, Ariz., 143. 

Icebergs in the Atlantic, 51. 

Ice-contact slopes, 162. 

Igneous rocks, 57. 

Independence, Cal., temperature, pre- 
cipitation, relative humidity, and 
sunshine, 270. 

Insequent streams, 107. 

Insolation at various latitudes, 13; 
local, daily, 12 ; and temperature, 16. 



288 



INDEX 



Ironstone Ridge, Pa., 150. 
Ishawooa Mesa, Wyo., 120. 
Island, tied, 194. 
Island Beach, N.J., 190. 
Isotherms, 33. 

Ithaca, N.Y., monthly temperatures at, 
227. 

Jenny Jump Mountain, N.J., 230. 
Jetties of the Mississippi, 81. 
Journal of Geography, cited, 237, 214. 
Juniata River, Pa., 103. 

Kaaterskill Creek, N.Y., 89. 
Kaibah Plateau, Ariz., 109. 
Kenesaw Mountain, Ga., 101. 
Kennebec River, Me., 210. 
Kettle lakes, 172. 

Key West, Fla., harbor, 209; tempera- 
ture and humidity, 24. 
Kittatinny peneplain, 137. 
Klamath Mountains, 266. 

Laccolithic mountains, 149. 

Lagoon, 190. 

Lakes, 170; consequent, 175 ; delta, 170; 
nearly drained, 176; due to faulting, 
175 ; morainic, 176 ; ox-bow, 170 ; in 
rock basins, 171 ; shore lines of, 195 ; 
solution, 175. 

Lake Atwood, Utah, 153. 

Lake Bonneville, 257. 

Lake Chelan, Washington, 272. 

Lake Ronkonkoma, N.Y., 156. 

Lake Tahoe, Cal., 266. 

Lancaster, Wis., 166. 

Lateral planation, 69, 80. 

Latitude, ascertainment of, 9. 

Latitude degrees, length of, 2. 

Lava cones, 150. 

Lava Park, Cal., 147. 

Lawson, A. C, cited, 199. 

Levees, natural, 78. 

Leverett, Frank, cited, 197. 

Limestone, 56. 

Little Chestnut Mountain, Tenn., 113. 

Long Hill, N.J., 230. 

Long Island, 155. 

Long Valley, Nev., 145, 265. 



Longitude, degrees in Fla. and Alaska, 
8; and time, 7. 

Lookout Mountain, 126. 

Los Angeles, Cal., temperature precipi- 
tation, relative humidity, and sun- 
shine at, 270. 

Lost Mountain, Ga., 101. 

Luminan Reef, Guam, 185. 

Lynn Beach, Mass., 194. 

McCook, Lake, Neb., 170. 

Mahanoy Ridge, Pa., 132. 

Map, contour, 60, 62. 

Maquoketa River, la., 169. 

Marblehead, Mass., harbor, 212. 

Mare Island, Cal., 208. 

Marysville Buttes, Cal., 148. 

Matfield River, Mass., 163. 

Mature (early) topography, 97. 

Mature topography and drainage, 98. 

Maumee Lake, 196. 

Maumee River, 176. 

Mauna Loa, Hawaiian Islands, 150. 

Meanders, flood plain, 85; incised, 103. 

Metedeconk Neck, N.J., 192. 

Mexico, monthly rainfall at, 26. 

Milksick Mountain, Tenn., 113. 

Minerals, 54. 

Minnehaha Falls, Minn., 166. 

Minnesota Valley, Minn., 166. 

Mississippi, delta, 80, 205; soils near, 

213; Valley (lower), 248. 
Missouri River, 79. 
Monadnock, 101. 
Monoclinal ridges, 127. 
Monoclinal shifting, 138; diagram to 

illustrate, 139. 
Monongahela River, Pa., 95. 
Moon's phases, 180. 
Moraine in N.Y., 226; ground, 157; 

marginal, 155, 157; soils on, 218, 219. 
Morristown, N.J., 231. 
Morro Bay, Cal., 197. 
Mountains, block, 144; anticlinal, 121, 

122; of circumerosion, 114; mature, 

116; synclinal, 126; volcanic, 147; 

youthful, 115. 
Mount Hilliers, Utah, 149. 
Mount Marcy, N.Y., 158. 
Mount Mazama, Oregon, 174. 



INDEX 



289 



Mount Mitchell, N.C., 118. 
Mount Shasta, Cal., 147, 152, 264. 

Nahant, Mass., 194. 

Narrow Back Mountain, 126. 

Nashville, Tenn., monthly temperature 
and precipitation at, 241. 

Nashville Basin, Tenn., 240. 

Navesink Highlands, N.J., 193. 

Navesink River, N.J., 193. 

New England, frosts in, 251. 

New England, southern, 249. 

New Haven, Conn., temperature and 
precipitation at, 251. 

New Jersey, temperature of highlands, 
232 ; of seacoast, 232. 

New Orleans harbor, 205; temperature 
and precipitation, 248; hourly tem- 
peratures, 260. 

New River, N.C., 238. 

New York, section across, 224. 

New York harbor, 204. 

Niagara, escarpment, 116; Falls, 110; 
River, 95. 

Nita Crevasse, La., 79. 

Nolichucky River, 238. 

Noon hour, ascertainment of, 8. 

Oakland, Cal., 208. 

Obsidian, 57. 

Ocean, 177. 

Ocean currents, 183. 

Oelrichs, S.D., temperatures aud pre- 
cipitation at, 255. 

Ohio River, 76. 

Oneida River, N.Y., 225. 

Ontario Lake, 225; Plain, 224. 

Opporto, monthly temperatures at, 18. 

Orote Peninsula, Guam, 186. 

Oswego, N.Y., monthly temperatures 
at, 227. 

Outcrop and dip, 135. 

Outliers, 117. 

Outwash plain, soils on, 219. 

Oxbow lakes, 86. 

Palisades (structure), 151. 
Palmyra, Wis., 156. 
Passaic Lake, 172, 173. 
Passaic River, N.J., 172. 



Paterson, N.J.,172, 173. 

Paxton Creek, Pa., 107, 136, 137. 

Peneplain, recently elevated, 101. 

Peneplains, Pa., 136. 

Peoria, 111., 88. 

Peters Mountain, Pa., 129, 130. 

Philadelphia, Pa., monthly tempera- 
tures at, 18. 

Piedmont Plateau in Md. and Va., 234; 
in N.J., 228. 

Pilot Knob, Tex., 149. 

Plain, mature and old, 223; youthful 
lake, 220. 

Platte River, Neb., 77; Wis., 167. 

Plattekill Creek, N.Y., 89. 

Plymouth, Mass., harbor, 212. 

Pocono sandstone, 126. 

Point Bonita, Cal., 187. 

Popular Science Monthly, cited, 244. 

Poquonoc River, Conn., 189. 

Portage, Wis., 167. 

Portland, Ore., hourly temperatures at, 
17 ; winds at, 272. 

Potomac River, Va., 134; Valley, Md.- 
Va., 135. 

Pottsville conglomerate, 126. 

Powell, J. W., cited, 258. 

Powell Creek, Pa., 136. 

Powell River, Va., 242. 

Princeton, N.J., 141. 

Provincetown, Mass., 200; harbor, 211. 

Quartzite, 58. 

Quito, monthly rainfall at, 26. 

Rainfall, equatorial, 26; monsoonal, 27; 

tropical, 26. 
Rainstorm, observations of a, 45. 
Raisin grape in California, 270. 
Red Mountain, Ga., 146. 
Red River Valley, N.D., 220 ; soils in, 221. 
Ridge belt in Md., Va., and W. Va., 235; 

N.J., 230; Pa., 244; Tenn., 239. 
Ridges, monoclinal, 124, 125. 
River, aggrading, 78; braided, 84; 

graded, 79; mature, 95; rejuvenated, 

101 ; terraces, 87 ; youthful, 95. 
Rochester, N.Y., 160. 
Rocks, 55; igneous, 57; metamorphic, 

57; outcrop, 59; sedimentary, 55. 



290 



INDEX 



Rocky Mountains, 139; eastern margin 

of, 255. 
Rocky River, O., 196. 
Rumson Neck, N.J., 193. 

Sacramento River, Cal., 79, 170, 265. 

Sailing routes in the Atlantic, 51. 

St. Anthony's Falls, 166. 

St. Helena, tides at, 181. 

St. Louis, Mo., monthly temperatures 

at, 16. 
St. Paul, Minn., 165. 
Salisbury, R. D., cited, 173. 
Salt Lake City, Utah, climate at, 24, 259 ; 

hourly temperatures at, 260. 
San Clemente Island, Cal., 198. 
San Francisco, Cal., harbor, 208; 

monthly temperatures at, 16; tides 

at, 183. 
San Francisco Mountains, Ariz., 262. 
San Luis Obispo Bay, Cal., 197. 
San Miguel River, Col., 154. 
Sand plains, 162. 
Sandstone, 56. 

Sandy Hook, N. J., 193 ; tides at, 180, 181. 
Santa Anna River, Cal., 84. 
Sawtooth Ridge, Wash., 273. 
Schist, 58. 

Schoharie Creek, N.Y., 89. 
Sea cliffs and wing spits, 191. 
Second Mountain, Pa., 127, 129, 130. 
Semple, E. C, cited, 237. 
Seneca Lake, N.Y., 225. 
Seneca Lake Valley, 163, 165. 
Sequatchie River, Tenn., 124. 
Sequatchie Valley, Tenn., 123. 
Sevier River Valley, Utah, soils in, 215. 
Shale, 55. 

Shamokin coal basin, Pa., 244. 
Sheepscott River, Me., 159. 
Shenandoah River, Va., 134. 
Shenandoah Valley, Va., 134; in the 

Civil War, 236. 
Shore lines, 187; of extinct lakes, 195. 
Short Hills, N.J., 172. 
Short Mountain, Tenn., 118. 
Shoshone River, Wyo., 78, 120. 
Shrewsbury River, N.J., 193. 
Sierras in Cal., 266; in Cal. and Nev., 

264. 



Sierra Valley, Cal., 176. 

Sill, 151. 

Sky in cyclones and anticyclones, 35. 

Slate, 58. 

Smith, W. S. T., cited, 199. 

Snickers Gap, Va., 134. 

Snowsheds in Cal., 269. 

Soils, 203; along aggrading river, 213; 
on alluvial fans, 214; on ground 
moraine, 218; on lake shores and 
bottoms, 216; on moraine, 219; on 
ridges, 217; in Sevier River Valley, 
215; on river terraces, 216; valley, 
215. 

Solution lakes, 175. 

South Platte River, Col., 140. 

Spear fish, S.D., temperature and pre- 
cipitation at, 255. 

Springfield, 111., monthly temperatures 
at, 19. 

Springs, 71. 

Spur, 110. 

Stage of erosion in regions of folded 
rock, 138. 

Stehekin River, Wash., 272. 

Straight Mountain, Ga., 146. 

Strawberry Hill, Mass., 195. 

Streams, map study of, 74; adjusted, 
133; adjustment in folded structure, 
132; anastomosing, 77; braided, 77; 
capture, 88; capture in folded rock, 
134; deposition, 68; diverted, 160; 
erosion, 68; field study of, 67; in- 
sequent, ' 106, 107; load, 68; sub- 
sequent, 106, 107; superimposed, 
104 ; tributaries, 71 ; valleys, 69. 

Sugar cane, 248. 

Sun Prairie, Wis., 161. 

Surprise Valley, Nev., 145. 

Susquehanna River, Pa., 104, 137, 245. 

Swamps on a flood plain, 170. 

Swatara Creek, Pa., 245. 

Synclinal valley, 121. 

Syncline, eroded, 127; with pitching 
axis, 128. 

Table Mountain, Col., 140. 
Tampa, Fla., temperature and precipi- 
tation at, 247. 
Tarr, R. S., cited, 116, 161, 194. 



INDEX 



291 



Temperature, as affected by altitude, 19 ; 

continental and marine, hourly, 17 ; 

monthly, 16; sensible, 259. 
Tennessee River, 239. 
Terraces, 87; soils on, 216; along the 

Ohio River, 102 ; wave-cut, 198. 
Texas, coast of, 206. 
Third Mountain, Pa., 128, 129, 130. 
Tidal currents, 182. 
Tides on smooth and indented coasts, 

180; daily, 178; daily high, 179; 

lagging of, 181 ; oceanic and coastal, 

182. 
Topography, subaerial and submarine, 

187. 
Town Hill, Md. (structure), 127. 
Trade winds in the Atlantic, 51. 
Trellis stream pattern, 108. 
Trenton area, N.J., soils in, 230. 
Tributaries, 71 ; reversed, 76. 
Trout Run, Pa., 133. 
Truckee, Cal., 269. 
Truckee River, Cal., 267. 
Truro, Mass., 188. 
Typical areas, studies of, 220. 

Uinkaret Mountains, Ariz., 262. 
Uinta Mountains, Utah, 153, 257. 
Uinta River, Utah, 153. 
Unaka Mountains, 238. 
Upham, Warren, cited, 92, 221. 

Valley, stream, 69; map, study of, 74; 
anticlinal, 123; hanging, 154; ice 
blocked, 171 ; in homogeneous and 
stratified rock, 113; longitudinal, 
108; mature, 95; rift, 144; trans- 
verse, 108; U-shaped, 154. 



Volcanic mountain, 147; dissected, 148; 
neck, 149. 

Walkers Mountain, Va., 130, 132. 

Warner Mountains, Cal., 264. 

Warren Lake, 196. 

Wasatch Mountains, Utah, 257. 

Watchung Mountains, N.J., 172, 230. 

Waterfall, study of a, 110. 

Water gap, 135. 

Watkins Glen, N.Y., 164. 

Weathering, curves, 72; field study of, 66. 

Weather map, construction of a, 29. 

Wekiwa Creek, Fla., 246. 

Wheat spring, climatic conditions of, 
222. 

Whitewater Lake, Wis., 156. 

Whittlesey, Lake, 196. 

Wicomico River, Md., 234. 

Wiconisco coal basin, Pa., 244. 

Willets Point, N.Y., tidal currents at, 
182. 

Wills Mountain, Md., 122. 

Wind directions in cyclones, 34 ; in anti- 
cyclones, 35. 

Wind gap, 135. 

Wing spits, 191. 

Wintun glacier, Cal., 152. 

Wissahickon Creek, Pa., 104. 

Withlacoochie River, Fla., 246. 

Wyoming formation, Col., 140. 

Yadkin River, N.C. 238. 
Yellowstone River, Wyo., 120. 
Youthful topography and drainage, 91. 
Yuma, Ariz., temperature, precipitation, 
and relative humidity at, 263. 

Zones, determination of, 4. 



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